Input TRS:
    1: incr(nil()) -> nil()
    2: incr(cons(X,L)) -> cons(s(X),incr(L))
    3: adx(nil()) -> nil()
    4: adx(cons(X,L)) -> incr(cons(X,adx(L)))
    5: nats() -> adx(zeros())
    6: zeros() -> cons(0(),zeros())
    7: head(cons(X,L)) -> X
    8: tail(cons(X,L)) -> L
Number of Rules: 8
Direct POLO(mPol) ... failed.