MAYBE

'Pop* with parameter subtitution (timeout of 60.0 seconds)'
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Answer:           MAYBE
Input Problem:    innermost runtime-complexity with respect to
  Rules:
    {  leq(0(), y) -> true()
     , leq(s(x), 0()) -> false()
     , leq(s(x), s(y)) -> leq(x, y)
     , if(true(), x, y) -> x
     , if(false(), x, y) -> y
     , -(x, 0()) -> x
     , -(s(x), s(y)) -> -(x, y)
     , mod(0(), y) -> 0()
     , mod(s(x), 0()) -> 0()
     , mod(s(x), s(y)) -> if(leq(y, x), mod(-(s(x), s(y)), s(y)), s(x))}

Proof Output:    
  The input cannot be shown compatible