MAYBE
* Step 1: Failure MAYBE
  + Considered Problem:
      - Strict TRS:
          head(cons(x,xs)) -> x
          if(false(),false(),y,xs,ys,x) -> sumList(ys,x)
          if(false(),true(),y,xs,ys,x) -> sumList(xs,y)
          if(true(),b,y,xs,ys,x) -> y
          inc(0()) -> s(0())
          inc(s(x)) -> s(inc(x))
          isEmpty(cons(x,xs)) -> false()
          isEmpty(nil()) -> true()
          isZero(0()) -> true()
          isZero(s(x)) -> false()
          p(0()) -> 0()
          p(s(0())) -> 0()
          p(s(s(x))) -> s(p(s(x)))
          sum(xs) -> sumList(xs,0())
          sumList(xs,y) -> if(isEmpty(xs),isZero(head(xs)),y,tail(xs),cons(p(head(xs)),tail(xs)),inc(y))
          tail(cons(x,xs)) -> xs
          tail(nil()) -> nil()
      - Signature:
          {head/1,if/6,inc/1,isEmpty/1,isZero/1,p/1,sum/1,sumList/2,tail/1} / {0/0,cons/2,false/0,nil/0,s/1,true/0}
      - Obligation:
          innermost runtime complexity wrt. defined symbols {head,if,inc,isEmpty,isZero,p,sum,sumList
          ,tail} and constructors {0,cons,false,nil,s,true}
  + Applied Processor:
      NaturalPI {shape = Mixed 3, restrict = NoRestrict, uargs = UArgs, urules = URules, selector = Nothing}
  + Details:
      Incompatible
MAYBE