* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            U11(mark(X1),X2) -> mark(U11(X1,X2))
            U11(ok(X1),ok(X2)) -> ok(U11(X1,X2))
            U12(mark(X1),X2) -> mark(U12(X1,X2))
            U12(ok(X1),ok(X2)) -> ok(U12(X1,X2))
            U13(mark(X)) -> mark(U13(X))
            U13(ok(X)) -> ok(U13(X))
            U21(mark(X1),X2) -> mark(U21(X1,X2))
            U21(ok(X1),ok(X2)) -> ok(U21(X1,X2))
            U22(mark(X1),X2) -> mark(U22(X1,X2))
            U22(ok(X1),ok(X2)) -> ok(U22(X1,X2))
            U23(mark(X)) -> mark(U23(X))
            U23(ok(X)) -> ok(U23(X))
            U31(mark(X1),X2) -> mark(U31(X1,X2))
            U31(ok(X1),ok(X2)) -> ok(U31(X1,X2))
            U32(mark(X1),X2) -> mark(U32(X1,X2))
            U32(ok(X1),ok(X2)) -> ok(U32(X1,X2))
            U33(mark(X)) -> mark(U33(X))
            U33(ok(X)) -> ok(U33(X))
            U41(mark(X1),X2,X3) -> mark(U41(X1,X2,X3))
            U41(ok(X1),ok(X2),ok(X3)) -> ok(U41(X1,X2,X3))
            U42(mark(X1),X2,X3) -> mark(U42(X1,X2,X3))
            U42(ok(X1),ok(X2),ok(X3)) -> ok(U42(X1,X2,X3))
            U43(mark(X1),X2,X3) -> mark(U43(X1,X2,X3))
            U43(ok(X1),ok(X2),ok(X3)) -> ok(U43(X1,X2,X3))
            U44(mark(X1),X2,X3) -> mark(U44(X1,X2,X3))
            U44(ok(X1),ok(X2),ok(X3)) -> ok(U44(X1,X2,X3))
            U45(mark(X1),X2) -> mark(U45(X1,X2))
            U45(ok(X1),ok(X2)) -> ok(U45(X1,X2))
            U46(mark(X)) -> mark(U46(X))
            U46(ok(X)) -> ok(U46(X))
            U51(mark(X1),X2) -> mark(U51(X1,X2))
            U51(ok(X1),ok(X2)) -> ok(U51(X1,X2))
            U52(mark(X)) -> mark(U52(X))
            U52(ok(X)) -> ok(U52(X))
            U61(mark(X)) -> mark(U61(X))
            U61(ok(X)) -> ok(U61(X))
            U71(mark(X)) -> mark(U71(X))
            U71(ok(X)) -> ok(U71(X))
            U81(mark(X1),X2,X3) -> mark(U81(X1,X2,X3))
            U81(ok(X1),ok(X2),ok(X3)) -> ok(U81(X1,X2,X3))
            U82(mark(X1),X2,X3) -> mark(U82(X1,X2,X3))
            U82(ok(X1),ok(X2),ok(X3)) -> ok(U82(X1,X2,X3))
            U83(mark(X1),X2,X3) -> mark(U83(X1,X2,X3))
            U83(ok(X1),ok(X2),ok(X3)) -> ok(U83(X1,X2,X3))
            U84(mark(X1),X2,X3) -> mark(U84(X1,X2,X3))
            U84(ok(X1),ok(X2),ok(X3)) -> ok(U84(X1,X2,X3))
            U85(mark(X1),X2) -> mark(U85(X1,X2))
            U85(ok(X1),ok(X2)) -> ok(U85(X1,X2))
            U86(mark(X)) -> mark(U86(X))
            U86(ok(X)) -> ok(U86(X))
            U91(mark(X1),X2,X3) -> mark(U91(X1,X2,X3))
            U91(ok(X1),ok(X2),ok(X3)) -> ok(U91(X1,X2,X3))
            U92(mark(X1),X2,X3) -> mark(U92(X1,X2,X3))
            U92(ok(X1),ok(X2),ok(X3)) -> ok(U92(X1,X2,X3))
            U93(mark(X1),X2,X3) -> mark(U93(X1,X2,X3))
            U93(ok(X1),ok(X2),ok(X3)) -> ok(U93(X1,X2,X3))
            U94(mark(X1),X2) -> mark(U94(X1,X2))
            U94(ok(X1),ok(X2)) -> ok(U94(X1,X2))
            active(U11(X1,X2)) -> U11(active(X1),X2)
            active(U11(tt(),V1)) -> mark(U12(isNatIListKind(V1),V1))
            active(U12(X1,X2)) -> U12(active(X1),X2)
            active(U12(tt(),V1)) -> mark(U13(isNatList(V1)))
            active(U13(X)) -> U13(active(X))
            active(U13(tt())) -> mark(tt())
            active(U21(X1,X2)) -> U21(active(X1),X2)
            active(U21(tt(),V1)) -> mark(U22(isNatKind(V1),V1))
            active(U22(X1,X2)) -> U22(active(X1),X2)
            active(U22(tt(),V1)) -> mark(U23(isNat(V1)))
            active(U23(X)) -> U23(active(X))
            active(U23(tt())) -> mark(tt())
            active(U31(X1,X2)) -> U31(active(X1),X2)
            active(U31(tt(),V)) -> mark(U32(isNatIListKind(V),V))
            active(U32(X1,X2)) -> U32(active(X1),X2)
            active(U32(tt(),V)) -> mark(U33(isNatList(V)))
            active(U33(X)) -> U33(active(X))
            active(U33(tt())) -> mark(tt())
            active(U41(X1,X2,X3)) -> U41(active(X1),X2,X3)
            active(U41(tt(),V1,V2)) -> mark(U42(isNatKind(V1),V1,V2))
            active(U42(X1,X2,X3)) -> U42(active(X1),X2,X3)
            active(U42(tt(),V1,V2)) -> mark(U43(isNatIListKind(V2),V1,V2))
            active(U43(X1,X2,X3)) -> U43(active(X1),X2,X3)
            active(U43(tt(),V1,V2)) -> mark(U44(isNatIListKind(V2),V1,V2))
            active(U44(X1,X2,X3)) -> U44(active(X1),X2,X3)
            active(U44(tt(),V1,V2)) -> mark(U45(isNat(V1),V2))
            active(U45(X1,X2)) -> U45(active(X1),X2)
            active(U45(tt(),V2)) -> mark(U46(isNatIList(V2)))
            active(U46(X)) -> U46(active(X))
            active(U46(tt())) -> mark(tt())
            active(U51(X1,X2)) -> U51(active(X1),X2)
            active(U51(tt(),V2)) -> mark(U52(isNatIListKind(V2)))
            active(U52(X)) -> U52(active(X))
            active(U52(tt())) -> mark(tt())
            active(U61(X)) -> U61(active(X))
            active(U61(tt())) -> mark(tt())
            active(U71(X)) -> U71(active(X))
            active(U71(tt())) -> mark(tt())
            active(U81(X1,X2,X3)) -> U81(active(X1),X2,X3)
            active(U81(tt(),V1,V2)) -> mark(U82(isNatKind(V1),V1,V2))
            active(U82(X1,X2,X3)) -> U82(active(X1),X2,X3)
            active(U82(tt(),V1,V2)) -> mark(U83(isNatIListKind(V2),V1,V2))
            active(U83(X1,X2,X3)) -> U83(active(X1),X2,X3)
            active(U83(tt(),V1,V2)) -> mark(U84(isNatIListKind(V2),V1,V2))
            active(U84(X1,X2,X3)) -> U84(active(X1),X2,X3)
            active(U84(tt(),V1,V2)) -> mark(U85(isNat(V1),V2))
            active(U85(X1,X2)) -> U85(active(X1),X2)
            active(U85(tt(),V2)) -> mark(U86(isNatList(V2)))
            active(U86(X)) -> U86(active(X))
            active(U86(tt())) -> mark(tt())
            active(U91(X1,X2,X3)) -> U91(active(X1),X2,X3)
            active(U91(tt(),L,N)) -> mark(U92(isNatIListKind(L),L,N))
            active(U92(X1,X2,X3)) -> U92(active(X1),X2,X3)
            active(U92(tt(),L,N)) -> mark(U93(isNat(N),L,N))
            active(U93(X1,X2,X3)) -> U93(active(X1),X2,X3)
            active(U93(tt(),L,N)) -> mark(U94(isNatKind(N),L))
            active(U94(X1,X2)) -> U94(active(X1),X2)
            active(U94(tt(),L)) -> mark(s(length(L)))
            active(cons(X1,X2)) -> cons(active(X1),X2)
            active(isNat(0())) -> mark(tt())
            active(isNat(length(V1))) -> mark(U11(isNatIListKind(V1),V1))
            active(isNat(s(V1))) -> mark(U21(isNatKind(V1),V1))
            active(isNatIList(V)) -> mark(U31(isNatIListKind(V),V))
            active(isNatIList(cons(V1,V2))) -> mark(U41(isNatKind(V1),V1,V2))
            active(isNatIList(zeros())) -> mark(tt())
            active(isNatIListKind(cons(V1,V2))) -> mark(U51(isNatKind(V1),V2))
            active(isNatIListKind(nil())) -> mark(tt())
            active(isNatIListKind(zeros())) -> mark(tt())
            active(isNatKind(0())) -> mark(tt())
            active(isNatKind(length(V1))) -> mark(U61(isNatIListKind(V1)))
            active(isNatKind(s(V1))) -> mark(U71(isNatKind(V1)))
            active(isNatList(cons(V1,V2))) -> mark(U81(isNatKind(V1),V1,V2))
            active(isNatList(nil())) -> mark(tt())
            active(length(X)) -> length(active(X))
            active(length(cons(N,L))) -> mark(U91(isNatList(L),L,N))
            active(length(nil())) -> mark(0())
            active(s(X)) -> s(active(X))
            active(zeros()) -> mark(cons(0(),zeros()))
            cons(mark(X1),X2) -> mark(cons(X1,X2))
            cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
            isNat(ok(X)) -> ok(isNat(X))
            isNatIList(ok(X)) -> ok(isNatIList(X))
            isNatIListKind(ok(X)) -> ok(isNatIListKind(X))
            isNatKind(ok(X)) -> ok(isNatKind(X))
            isNatList(ok(X)) -> ok(isNatList(X))
            length(mark(X)) -> mark(length(X))
            length(ok(X)) -> ok(length(X))
            proper(0()) -> ok(0())
            proper(U11(X1,X2)) -> U11(proper(X1),proper(X2))
            proper(U12(X1,X2)) -> U12(proper(X1),proper(X2))
            proper(U13(X)) -> U13(proper(X))
            proper(U21(X1,X2)) -> U21(proper(X1),proper(X2))
            proper(U22(X1,X2)) -> U22(proper(X1),proper(X2))
            proper(U23(X)) -> U23(proper(X))
            proper(U31(X1,X2)) -> U31(proper(X1),proper(X2))
            proper(U32(X1,X2)) -> U32(proper(X1),proper(X2))
            proper(U33(X)) -> U33(proper(X))
            proper(U41(X1,X2,X3)) -> U41(proper(X1),proper(X2),proper(X3))
            proper(U42(X1,X2,X3)) -> U42(proper(X1),proper(X2),proper(X3))
            proper(U43(X1,X2,X3)) -> U43(proper(X1),proper(X2),proper(X3))
            proper(U44(X1,X2,X3)) -> U44(proper(X1),proper(X2),proper(X3))
            proper(U45(X1,X2)) -> U45(proper(X1),proper(X2))
            proper(U46(X)) -> U46(proper(X))
            proper(U51(X1,X2)) -> U51(proper(X1),proper(X2))
            proper(U52(X)) -> U52(proper(X))
            proper(U61(X)) -> U61(proper(X))
            proper(U71(X)) -> U71(proper(X))
            proper(U81(X1,X2,X3)) -> U81(proper(X1),proper(X2),proper(X3))
            proper(U82(X1,X2,X3)) -> U82(proper(X1),proper(X2),proper(X3))
            proper(U83(X1,X2,X3)) -> U83(proper(X1),proper(X2),proper(X3))
            proper(U84(X1,X2,X3)) -> U84(proper(X1),proper(X2),proper(X3))
            proper(U85(X1,X2)) -> U85(proper(X1),proper(X2))
            proper(U86(X)) -> U86(proper(X))
            proper(U91(X1,X2,X3)) -> U91(proper(X1),proper(X2),proper(X3))
            proper(U92(X1,X2,X3)) -> U92(proper(X1),proper(X2),proper(X3))
            proper(U93(X1,X2,X3)) -> U93(proper(X1),proper(X2),proper(X3))
            proper(U94(X1,X2)) -> U94(proper(X1),proper(X2))
            proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
            proper(isNat(X)) -> isNat(proper(X))
            proper(isNatIList(X)) -> isNatIList(proper(X))
            proper(isNatIListKind(X)) -> isNatIListKind(proper(X))
            proper(isNatKind(X)) -> isNatKind(proper(X))
            proper(isNatList(X)) -> isNatList(proper(X))
            proper(length(X)) -> length(proper(X))
            proper(nil()) -> ok(nil())
            proper(s(X)) -> s(proper(X))
            proper(tt()) -> ok(tt())
            proper(zeros()) -> ok(zeros())
            s(mark(X)) -> mark(s(X))
            s(ok(X)) -> ok(s(X))
            top(mark(X)) -> top(proper(X))
            top(ok(X)) -> top(active(X))
        - Signature:
            {U11/2,U12/2,U13/1,U21/2,U22/2,U23/1,U31/2,U32/2,U33/1,U41/3,U42/3,U43/3,U44/3,U45/2,U46/1,U51/2,U52/1,U61/1
            ,U71/1,U81/3,U82/3,U83/3,U84/3,U85/2,U86/1,U91/3,U92/3,U93/3,U94/2,active/1,cons/2,isNat/1,isNatIList/1
            ,isNatIListKind/1,isNatKind/1,isNatList/1,length/1,proper/1,s/1,top/1} / {0/0,mark/1,nil/0,ok/1,tt/0
            ,zeros/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {U11,U12,U13,U21,U22,U23,U31,U32,U33,U41,U42,U43,U44,U45
            ,U46,U51,U52,U61,U71,U81,U82,U83,U84,U85,U86,U91,U92,U93,U94,active,cons,isNat,isNatIList,isNatIListKind
            ,isNatKind,isNatList,length,proper,s,top} and constructors {0,mark,nil,ok,tt,zeros}
    + Applied Processor:
        Sum {left = someStrategy, right = someStrategy}
    + Details:
        ()
* Step 2: DecreasingLoops WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            U11(mark(X1),X2) -> mark(U11(X1,X2))
            U11(ok(X1),ok(X2)) -> ok(U11(X1,X2))
            U12(mark(X1),X2) -> mark(U12(X1,X2))
            U12(ok(X1),ok(X2)) -> ok(U12(X1,X2))
            U13(mark(X)) -> mark(U13(X))
            U13(ok(X)) -> ok(U13(X))
            U21(mark(X1),X2) -> mark(U21(X1,X2))
            U21(ok(X1),ok(X2)) -> ok(U21(X1,X2))
            U22(mark(X1),X2) -> mark(U22(X1,X2))
            U22(ok(X1),ok(X2)) -> ok(U22(X1,X2))
            U23(mark(X)) -> mark(U23(X))
            U23(ok(X)) -> ok(U23(X))
            U31(mark(X1),X2) -> mark(U31(X1,X2))
            U31(ok(X1),ok(X2)) -> ok(U31(X1,X2))
            U32(mark(X1),X2) -> mark(U32(X1,X2))
            U32(ok(X1),ok(X2)) -> ok(U32(X1,X2))
            U33(mark(X)) -> mark(U33(X))
            U33(ok(X)) -> ok(U33(X))
            U41(mark(X1),X2,X3) -> mark(U41(X1,X2,X3))
            U41(ok(X1),ok(X2),ok(X3)) -> ok(U41(X1,X2,X3))
            U42(mark(X1),X2,X3) -> mark(U42(X1,X2,X3))
            U42(ok(X1),ok(X2),ok(X3)) -> ok(U42(X1,X2,X3))
            U43(mark(X1),X2,X3) -> mark(U43(X1,X2,X3))
            U43(ok(X1),ok(X2),ok(X3)) -> ok(U43(X1,X2,X3))
            U44(mark(X1),X2,X3) -> mark(U44(X1,X2,X3))
            U44(ok(X1),ok(X2),ok(X3)) -> ok(U44(X1,X2,X3))
            U45(mark(X1),X2) -> mark(U45(X1,X2))
            U45(ok(X1),ok(X2)) -> ok(U45(X1,X2))
            U46(mark(X)) -> mark(U46(X))
            U46(ok(X)) -> ok(U46(X))
            U51(mark(X1),X2) -> mark(U51(X1,X2))
            U51(ok(X1),ok(X2)) -> ok(U51(X1,X2))
            U52(mark(X)) -> mark(U52(X))
            U52(ok(X)) -> ok(U52(X))
            U61(mark(X)) -> mark(U61(X))
            U61(ok(X)) -> ok(U61(X))
            U71(mark(X)) -> mark(U71(X))
            U71(ok(X)) -> ok(U71(X))
            U81(mark(X1),X2,X3) -> mark(U81(X1,X2,X3))
            U81(ok(X1),ok(X2),ok(X3)) -> ok(U81(X1,X2,X3))
            U82(mark(X1),X2,X3) -> mark(U82(X1,X2,X3))
            U82(ok(X1),ok(X2),ok(X3)) -> ok(U82(X1,X2,X3))
            U83(mark(X1),X2,X3) -> mark(U83(X1,X2,X3))
            U83(ok(X1),ok(X2),ok(X3)) -> ok(U83(X1,X2,X3))
            U84(mark(X1),X2,X3) -> mark(U84(X1,X2,X3))
            U84(ok(X1),ok(X2),ok(X3)) -> ok(U84(X1,X2,X3))
            U85(mark(X1),X2) -> mark(U85(X1,X2))
            U85(ok(X1),ok(X2)) -> ok(U85(X1,X2))
            U86(mark(X)) -> mark(U86(X))
            U86(ok(X)) -> ok(U86(X))
            U91(mark(X1),X2,X3) -> mark(U91(X1,X2,X3))
            U91(ok(X1),ok(X2),ok(X3)) -> ok(U91(X1,X2,X3))
            U92(mark(X1),X2,X3) -> mark(U92(X1,X2,X3))
            U92(ok(X1),ok(X2),ok(X3)) -> ok(U92(X1,X2,X3))
            U93(mark(X1),X2,X3) -> mark(U93(X1,X2,X3))
            U93(ok(X1),ok(X2),ok(X3)) -> ok(U93(X1,X2,X3))
            U94(mark(X1),X2) -> mark(U94(X1,X2))
            U94(ok(X1),ok(X2)) -> ok(U94(X1,X2))
            active(U11(X1,X2)) -> U11(active(X1),X2)
            active(U11(tt(),V1)) -> mark(U12(isNatIListKind(V1),V1))
            active(U12(X1,X2)) -> U12(active(X1),X2)
            active(U12(tt(),V1)) -> mark(U13(isNatList(V1)))
            active(U13(X)) -> U13(active(X))
            active(U13(tt())) -> mark(tt())
            active(U21(X1,X2)) -> U21(active(X1),X2)
            active(U21(tt(),V1)) -> mark(U22(isNatKind(V1),V1))
            active(U22(X1,X2)) -> U22(active(X1),X2)
            active(U22(tt(),V1)) -> mark(U23(isNat(V1)))
            active(U23(X)) -> U23(active(X))
            active(U23(tt())) -> mark(tt())
            active(U31(X1,X2)) -> U31(active(X1),X2)
            active(U31(tt(),V)) -> mark(U32(isNatIListKind(V),V))
            active(U32(X1,X2)) -> U32(active(X1),X2)
            active(U32(tt(),V)) -> mark(U33(isNatList(V)))
            active(U33(X)) -> U33(active(X))
            active(U33(tt())) -> mark(tt())
            active(U41(X1,X2,X3)) -> U41(active(X1),X2,X3)
            active(U41(tt(),V1,V2)) -> mark(U42(isNatKind(V1),V1,V2))
            active(U42(X1,X2,X3)) -> U42(active(X1),X2,X3)
            active(U42(tt(),V1,V2)) -> mark(U43(isNatIListKind(V2),V1,V2))
            active(U43(X1,X2,X3)) -> U43(active(X1),X2,X3)
            active(U43(tt(),V1,V2)) -> mark(U44(isNatIListKind(V2),V1,V2))
            active(U44(X1,X2,X3)) -> U44(active(X1),X2,X3)
            active(U44(tt(),V1,V2)) -> mark(U45(isNat(V1),V2))
            active(U45(X1,X2)) -> U45(active(X1),X2)
            active(U45(tt(),V2)) -> mark(U46(isNatIList(V2)))
            active(U46(X)) -> U46(active(X))
            active(U46(tt())) -> mark(tt())
            active(U51(X1,X2)) -> U51(active(X1),X2)
            active(U51(tt(),V2)) -> mark(U52(isNatIListKind(V2)))
            active(U52(X)) -> U52(active(X))
            active(U52(tt())) -> mark(tt())
            active(U61(X)) -> U61(active(X))
            active(U61(tt())) -> mark(tt())
            active(U71(X)) -> U71(active(X))
            active(U71(tt())) -> mark(tt())
            active(U81(X1,X2,X3)) -> U81(active(X1),X2,X3)
            active(U81(tt(),V1,V2)) -> mark(U82(isNatKind(V1),V1,V2))
            active(U82(X1,X2,X3)) -> U82(active(X1),X2,X3)
            active(U82(tt(),V1,V2)) -> mark(U83(isNatIListKind(V2),V1,V2))
            active(U83(X1,X2,X3)) -> U83(active(X1),X2,X3)
            active(U83(tt(),V1,V2)) -> mark(U84(isNatIListKind(V2),V1,V2))
            active(U84(X1,X2,X3)) -> U84(active(X1),X2,X3)
            active(U84(tt(),V1,V2)) -> mark(U85(isNat(V1),V2))
            active(U85(X1,X2)) -> U85(active(X1),X2)
            active(U85(tt(),V2)) -> mark(U86(isNatList(V2)))
            active(U86(X)) -> U86(active(X))
            active(U86(tt())) -> mark(tt())
            active(U91(X1,X2,X3)) -> U91(active(X1),X2,X3)
            active(U91(tt(),L,N)) -> mark(U92(isNatIListKind(L),L,N))
            active(U92(X1,X2,X3)) -> U92(active(X1),X2,X3)
            active(U92(tt(),L,N)) -> mark(U93(isNat(N),L,N))
            active(U93(X1,X2,X3)) -> U93(active(X1),X2,X3)
            active(U93(tt(),L,N)) -> mark(U94(isNatKind(N),L))
            active(U94(X1,X2)) -> U94(active(X1),X2)
            active(U94(tt(),L)) -> mark(s(length(L)))
            active(cons(X1,X2)) -> cons(active(X1),X2)
            active(isNat(0())) -> mark(tt())
            active(isNat(length(V1))) -> mark(U11(isNatIListKind(V1),V1))
            active(isNat(s(V1))) -> mark(U21(isNatKind(V1),V1))
            active(isNatIList(V)) -> mark(U31(isNatIListKind(V),V))
            active(isNatIList(cons(V1,V2))) -> mark(U41(isNatKind(V1),V1,V2))
            active(isNatIList(zeros())) -> mark(tt())
            active(isNatIListKind(cons(V1,V2))) -> mark(U51(isNatKind(V1),V2))
            active(isNatIListKind(nil())) -> mark(tt())
            active(isNatIListKind(zeros())) -> mark(tt())
            active(isNatKind(0())) -> mark(tt())
            active(isNatKind(length(V1))) -> mark(U61(isNatIListKind(V1)))
            active(isNatKind(s(V1))) -> mark(U71(isNatKind(V1)))
            active(isNatList(cons(V1,V2))) -> mark(U81(isNatKind(V1),V1,V2))
            active(isNatList(nil())) -> mark(tt())
            active(length(X)) -> length(active(X))
            active(length(cons(N,L))) -> mark(U91(isNatList(L),L,N))
            active(length(nil())) -> mark(0())
            active(s(X)) -> s(active(X))
            active(zeros()) -> mark(cons(0(),zeros()))
            cons(mark(X1),X2) -> mark(cons(X1,X2))
            cons(ok(X1),ok(X2)) -> ok(cons(X1,X2))
            isNat(ok(X)) -> ok(isNat(X))
            isNatIList(ok(X)) -> ok(isNatIList(X))
            isNatIListKind(ok(X)) -> ok(isNatIListKind(X))
            isNatKind(ok(X)) -> ok(isNatKind(X))
            isNatList(ok(X)) -> ok(isNatList(X))
            length(mark(X)) -> mark(length(X))
            length(ok(X)) -> ok(length(X))
            proper(0()) -> ok(0())
            proper(U11(X1,X2)) -> U11(proper(X1),proper(X2))
            proper(U12(X1,X2)) -> U12(proper(X1),proper(X2))
            proper(U13(X)) -> U13(proper(X))
            proper(U21(X1,X2)) -> U21(proper(X1),proper(X2))
            proper(U22(X1,X2)) -> U22(proper(X1),proper(X2))
            proper(U23(X)) -> U23(proper(X))
            proper(U31(X1,X2)) -> U31(proper(X1),proper(X2))
            proper(U32(X1,X2)) -> U32(proper(X1),proper(X2))
            proper(U33(X)) -> U33(proper(X))
            proper(U41(X1,X2,X3)) -> U41(proper(X1),proper(X2),proper(X3))
            proper(U42(X1,X2,X3)) -> U42(proper(X1),proper(X2),proper(X3))
            proper(U43(X1,X2,X3)) -> U43(proper(X1),proper(X2),proper(X3))
            proper(U44(X1,X2,X3)) -> U44(proper(X1),proper(X2),proper(X3))
            proper(U45(X1,X2)) -> U45(proper(X1),proper(X2))
            proper(U46(X)) -> U46(proper(X))
            proper(U51(X1,X2)) -> U51(proper(X1),proper(X2))
            proper(U52(X)) -> U52(proper(X))
            proper(U61(X)) -> U61(proper(X))
            proper(U71(X)) -> U71(proper(X))
            proper(U81(X1,X2,X3)) -> U81(proper(X1),proper(X2),proper(X3))
            proper(U82(X1,X2,X3)) -> U82(proper(X1),proper(X2),proper(X3))
            proper(U83(X1,X2,X3)) -> U83(proper(X1),proper(X2),proper(X3))
            proper(U84(X1,X2,X3)) -> U84(proper(X1),proper(X2),proper(X3))
            proper(U85(X1,X2)) -> U85(proper(X1),proper(X2))
            proper(U86(X)) -> U86(proper(X))
            proper(U91(X1,X2,X3)) -> U91(proper(X1),proper(X2),proper(X3))
            proper(U92(X1,X2,X3)) -> U92(proper(X1),proper(X2),proper(X3))
            proper(U93(X1,X2,X3)) -> U93(proper(X1),proper(X2),proper(X3))
            proper(U94(X1,X2)) -> U94(proper(X1),proper(X2))
            proper(cons(X1,X2)) -> cons(proper(X1),proper(X2))
            proper(isNat(X)) -> isNat(proper(X))
            proper(isNatIList(X)) -> isNatIList(proper(X))
            proper(isNatIListKind(X)) -> isNatIListKind(proper(X))
            proper(isNatKind(X)) -> isNatKind(proper(X))
            proper(isNatList(X)) -> isNatList(proper(X))
            proper(length(X)) -> length(proper(X))
            proper(nil()) -> ok(nil())
            proper(s(X)) -> s(proper(X))
            proper(tt()) -> ok(tt())
            proper(zeros()) -> ok(zeros())
            s(mark(X)) -> mark(s(X))
            s(ok(X)) -> ok(s(X))
            top(mark(X)) -> top(proper(X))
            top(ok(X)) -> top(active(X))
        - Signature:
            {U11/2,U12/2,U13/1,U21/2,U22/2,U23/1,U31/2,U32/2,U33/1,U41/3,U42/3,U43/3,U44/3,U45/2,U46/1,U51/2,U52/1,U61/1
            ,U71/1,U81/3,U82/3,U83/3,U84/3,U85/2,U86/1,U91/3,U92/3,U93/3,U94/2,active/1,cons/2,isNat/1,isNatIList/1
            ,isNatIListKind/1,isNatKind/1,isNatList/1,length/1,proper/1,s/1,top/1} / {0/0,mark/1,nil/0,ok/1,tt/0
            ,zeros/0}
        - Obligation:
            innermost runtime complexity wrt. defined symbols {U11,U12,U13,U21,U22,U23,U31,U32,U33,U41,U42,U43,U44,U45
            ,U46,U51,U52,U61,U71,U81,U82,U83,U84,U85,U86,U91,U92,U93,U94,active,cons,isNat,isNatIList,isNatIListKind
            ,isNatKind,isNatList,length,proper,s,top} and constructors {0,mark,nil,ok,tt,zeros}
    + Applied Processor:
        DecreasingLoops {bound = AnyLoop, narrow = 10}
    + Details:
        The system has following decreasing Loops:
          U11(x,y){x -> mark(x)} =
            U11(mark(x),y) ->^+ mark(U11(x,y))
              = C[U11(x,y) = U11(x,y){}]

WORST_CASE(Omega(n^1),?)