* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            U11(mark(X)) -> mark(U11(X))
            U11(ok(X)) -> ok(U11(X))
            U21(mark(X)) -> mark(U21(X))
            U21(ok(X)) -> ok(U21(X))
            U31(mark(X)) -> mark(U31(X))
            U31(ok(X)) -> ok(U31(X))
            U41(mark(X1),X2) -> mark(U41(X1,X2))
            U41(ok(X1),ok(X2)) -> ok(U41(X1,X2))
            U42(mark(X)) -> mark(U42(X))
            U42(ok(X)) -> ok(U42(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(X1),X2,X3) -> mark(U61(X1,X2,X3))
            U61(ok(X1),ok(X2),ok(X3)) -> ok(U61(X1,X2,X3))
            U62(mark(X1),X2) -> mark(U62(X1,X2))
            U62(ok(X1),ok(X2)) -> ok(U62(X1,X2))
            active(U11(X)) -> U11(active(X))
            active(U11(tt())) -> mark(tt())
            active(U21(X)) -> U21(active(X))
            active(U21(tt())) -> mark(tt())
            active(U31(X)) -> U31(active(X))
            active(U31(tt())) -> mark(tt())
            active(U41(X1,X2)) -> U41(active(X1),X2)
            active(U41(tt(),V2)) -> mark(U42(isNatIList(V2)))
            active(U42(X)) -> U42(active(X))
            active(U42(tt())) -> mark(tt())
            active(U51(X1,X2)) -> U51(active(X1),X2)
            active(U51(tt(),V2)) -> mark(U52(isNatList(V2)))
            active(U52(X)) -> U52(active(X))
            active(U52(tt())) -> mark(tt())
            active(U61(X1,X2,X3)) -> U61(active(X1),X2,X3)
            active(U61(tt(),L,N)) -> mark(U62(isNat(N),L))
            active(U62(X1,X2)) -> U62(active(X1),X2)
            active(U62(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(isNatList(V1)))
            active(isNat(s(V1))) -> mark(U21(isNat(V1)))
            active(isNatIList(V)) -> mark(U31(isNatList(V)))
            active(isNatIList(cons(V1,V2))) -> mark(U41(isNat(V1),V2))
            active(isNatIList(zeros())) -> mark(tt())
            active(isNatList(cons(V1,V2))) -> mark(U51(isNat(V1),V2))
            active(isNatList(nil())) -> mark(tt())
            active(length(X)) -> length(active(X))
            active(length(cons(N,L))) -> mark(U61(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))
            isNatList(ok(X)) -> ok(isNatList(X))
            length(mark(X)) -> mark(length(X))
            length(ok(X)) -> ok(length(X))
            proper(0()) -> ok(0())
            proper(U11(X)) -> U11(proper(X))
            proper(U21(X)) -> U21(proper(X))
            proper(U31(X)) -> U31(proper(X))
            proper(U41(X1,X2)) -> U41(proper(X1),proper(X2))
            proper(U42(X)) -> U42(proper(X))
            proper(U51(X1,X2)) -> U51(proper(X1),proper(X2))
            proper(U52(X)) -> U52(proper(X))
            proper(U61(X1,X2,X3)) -> U61(proper(X1),proper(X2),proper(X3))
            proper(U62(X1,X2)) -> U62(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(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:
            {U11/1,U21/1,U31/1,U41/2,U42/1,U51/2,U52/1,U61/3,U62/2,active/1,cons/2,isNat/1,isNatIList/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,U21,U31,U41,U42,U51,U52,U61,U62,active,cons,isNat
            ,isNatIList,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(X)) -> mark(U11(X))
            U11(ok(X)) -> ok(U11(X))
            U21(mark(X)) -> mark(U21(X))
            U21(ok(X)) -> ok(U21(X))
            U31(mark(X)) -> mark(U31(X))
            U31(ok(X)) -> ok(U31(X))
            U41(mark(X1),X2) -> mark(U41(X1,X2))
            U41(ok(X1),ok(X2)) -> ok(U41(X1,X2))
            U42(mark(X)) -> mark(U42(X))
            U42(ok(X)) -> ok(U42(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(X1),X2,X3) -> mark(U61(X1,X2,X3))
            U61(ok(X1),ok(X2),ok(X3)) -> ok(U61(X1,X2,X3))
            U62(mark(X1),X2) -> mark(U62(X1,X2))
            U62(ok(X1),ok(X2)) -> ok(U62(X1,X2))
            active(U11(X)) -> U11(active(X))
            active(U11(tt())) -> mark(tt())
            active(U21(X)) -> U21(active(X))
            active(U21(tt())) -> mark(tt())
            active(U31(X)) -> U31(active(X))
            active(U31(tt())) -> mark(tt())
            active(U41(X1,X2)) -> U41(active(X1),X2)
            active(U41(tt(),V2)) -> mark(U42(isNatIList(V2)))
            active(U42(X)) -> U42(active(X))
            active(U42(tt())) -> mark(tt())
            active(U51(X1,X2)) -> U51(active(X1),X2)
            active(U51(tt(),V2)) -> mark(U52(isNatList(V2)))
            active(U52(X)) -> U52(active(X))
            active(U52(tt())) -> mark(tt())
            active(U61(X1,X2,X3)) -> U61(active(X1),X2,X3)
            active(U61(tt(),L,N)) -> mark(U62(isNat(N),L))
            active(U62(X1,X2)) -> U62(active(X1),X2)
            active(U62(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(isNatList(V1)))
            active(isNat(s(V1))) -> mark(U21(isNat(V1)))
            active(isNatIList(V)) -> mark(U31(isNatList(V)))
            active(isNatIList(cons(V1,V2))) -> mark(U41(isNat(V1),V2))
            active(isNatIList(zeros())) -> mark(tt())
            active(isNatList(cons(V1,V2))) -> mark(U51(isNat(V1),V2))
            active(isNatList(nil())) -> mark(tt())
            active(length(X)) -> length(active(X))
            active(length(cons(N,L))) -> mark(U61(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))
            isNatList(ok(X)) -> ok(isNatList(X))
            length(mark(X)) -> mark(length(X))
            length(ok(X)) -> ok(length(X))
            proper(0()) -> ok(0())
            proper(U11(X)) -> U11(proper(X))
            proper(U21(X)) -> U21(proper(X))
            proper(U31(X)) -> U31(proper(X))
            proper(U41(X1,X2)) -> U41(proper(X1),proper(X2))
            proper(U42(X)) -> U42(proper(X))
            proper(U51(X1,X2)) -> U51(proper(X1),proper(X2))
            proper(U52(X)) -> U52(proper(X))
            proper(U61(X1,X2,X3)) -> U61(proper(X1),proper(X2),proper(X3))
            proper(U62(X1,X2)) -> U62(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(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:
            {U11/1,U21/1,U31/1,U41/2,U42/1,U51/2,U52/1,U61/3,U62/2,active/1,cons/2,isNat/1,isNatIList/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,U21,U31,U41,U42,U51,U52,U61,U62,active,cons,isNat
            ,isNatIList,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){x -> mark(x)} =
            U11(mark(x)) ->^+ mark(U11(x))
              = C[U11(x) = U11(x){}]

WORST_CASE(Omega(n^1),?)