Input TRS:
    1: active(zeros()) -> mark(cons(0(),zeros()))
    2: active(U11(tt(),L)) -> mark(U12(tt(),L))
    3: active(U12(tt(),L)) -> mark(s(length(L)))
    4: active(length(nil())) -> mark(0())
    5: active(length(cons(N,L))) -> mark(U11(tt(),L))
    6: mark(zeros()) -> active(zeros())
    7: mark(cons(X1,X2)) -> active(cons(mark(X1),X2))
    8: mark(0()) -> active(0())
    9: mark(U11(X1,X2)) -> active(U11(mark(X1),X2))
    10: mark(tt()) -> active(tt())
    11: mark(U12(X1,X2)) -> active(U12(mark(X1),X2))
    12: mark(s(X)) -> active(s(mark(X)))
    13: mark(length(X)) -> active(length(mark(X)))
    14: mark(nil()) -> active(nil())
    15: cons(mark(X1),X2) -> cons(X1,X2)
    16: cons(X1,mark(X2)) -> cons(X1,X2)
    17: cons(active(X1),X2) -> cons(X1,X2)
    18: cons(X1,active(X2)) -> cons(X1,X2)
    19: U11(mark(X1),X2) -> U11(X1,X2)
    20: U11(X1,mark(X2)) -> U11(X1,X2)
    21: U11(active(X1),X2) -> U11(X1,X2)
    22: U11(X1,active(X2)) -> U11(X1,X2)
    23: U12(mark(X1),X2) -> U12(X1,X2)
    24: U12(X1,mark(X2)) -> U12(X1,X2)
    25: U12(active(X1),X2) -> U12(X1,X2)
    26: U12(X1,active(X2)) -> U12(X1,X2)
    27: s(mark(X)) -> s(X)
    28: s(active(X)) -> s(X)
    29: length(mark(X)) -> length(X)
    30: length(active(X)) -> length(X)
Number of Rules: 30
Direct QWPOS(Sum) ... failed.