Input TRS:
    1: active(zz(zz(X,Y),Z)) -> mark(zz(X,zz(Y,Z)))
    2: active(zz(X,nil())) -> mark(X)
    3: active(zz(nil(),X)) -> mark(X)
    4: active(U11(tt())) -> mark(U12(tt()))
    5: active(U12(tt())) -> mark(tt())
    6: active(isNePal(zz(I,zz(P,I)))) -> mark(U11(tt()))
    7: mark(zz(X1,X2)) -> active(zz(mark(X1),mark(X2)))
    8: mark(nil()) -> active(nil())
    9: mark(U11(X)) -> active(U11(mark(X)))
    10: mark(tt()) -> active(tt())
    11: mark(U12(X)) -> active(U12(mark(X)))
    12: mark(isNePal(X)) -> active(isNePal(mark(X)))
    13: zz(mark(X1),X2) -> zz(X1,X2)
    14: zz(X1,mark(X2)) -> zz(X1,X2)
    15: zz(active(X1),X2) -> zz(X1,X2)
    16: zz(X1,active(X2)) -> zz(X1,X2)
    17: U11(mark(X)) -> U11(X)
    18: U11(active(X)) -> U11(X)
    19: U12(mark(X)) -> U12(X)
    20: U12(active(X)) -> U12(X)
    21: isNePal(mark(X)) -> isNePal(X)
    22: isNePal(active(X)) -> isNePal(X)
Number of Rules: 22
Direct POLO(mPol) ... failed.