Input TRS:
    1: a__f(X) -> a__if(mark(X),c(),f(true()))
    2: a__if(true(),X,Y) -> mark(X)
    3: a__if(false(),X,Y) -> mark(Y)
    4: mark(f(X)) -> a__f(mark(X))
    5: mark(if(X1,X2,X3)) -> a__if(mark(X1),mark(X2),X3)
    6: mark(c()) -> c()
    7: mark(true()) -> true()
    8: mark(false()) -> false()
    9: a__f(X) -> f(X)
    10: a__if(X1,X2,X3) -> if(X1,X2,X3)
Number of Rules: 10
Direct QWPOS(mPol) ... failed.