TRS:
 {  p(m, n, s(r)) -> p(m, r, n),
  p(m, s(n), 0()) -> p(0(), n, m),
   p(m, 0(), 0()) -> m}
 POP*:
  Quasi-Precedence:
  empty
  
Normal:
   pi(p) = [1,2,3]
  
Safe:
   pi(s) = [1]
  
Predicative System:
   {  p(m,n,s(;r);) -> p(m,r,n;),
    p(m,s(;n),0();) -> p(0(),n,m;),
      p(m,0(),0();) -> m}
  Qed