* Step 1: Sum WORST_CASE(Omega(n^1),?)
    + Considered Problem:
        - Strict TRS:
            ++(.(x,y),z) -> .(x,++(y,z))
            ++(nil(),y) -> y
            if(false(),x,y) -> x
            if(true(),x,y) -> x
            merge(x,nil()) -> x
            merge(.(x,y),.(u,v)) -> if(<(x,u),.(x,merge(y,.(u,v))),.(u,merge(.(x,y),v)))
            merge(nil(),y) -> y
        - Signature:
            {++/2,if/3,merge/2} / {./2, .(x,++(y,z))
            ++(nil(),y) -> y
            if(false(),x,y) -> x
            if(true(),x,y) -> x
            merge(x,nil()) -> x
            merge(.(x,y),.(u,v)) -> if(<(x,u),.(x,merge(y,.(u,v))),.(u,merge(.(x,y),v)))
            merge(nil(),y) -> y
        - Signature:
            {++/2,if/3,merge/2} / {./2, .(x,y)} =
            ++(.(x,y),z) ->^+ .(x,++(y,z))
              = C[++(y,z) = ++(y,z){}]

WORST_CASE(Omega(n^1),?)