Input TRS:
    1: f(x,x) -> f(i(x),g(g(x)))
    2: f(x,y) -> x
    3: g(x) -> i(x)
    4: f(x,i(x)) -> f(x,x)
    5: f(i(x),i(g(x))) -> a()
Number of Rules: 5
Direct POLO(Pol) ... failed.