MAYBE
LCTRS
  Theories
    Core, Ints
  Signature
    return: Int -> Int
    sum1: Int -> Int
    u: (Int, Int, Int) -> Int
  Rules
    sum1(!n) -> u(!n, 1, 0)
    u(!n, !i, !k) -> u(!n, +(!i, 1), +(!k, !i)) [<=(!i, !n)]
    u(!n, !i, !k) -> return(!k) [not(<=(!i, !n))]
No termination info given.

Elapsed Time:  38.14 ms