MAYBE
LCTRS
  Theories
    Core, Ints
  Sorts
    Unit
  Signature
    fastfib: Int -> Unit
    return: Int -> Unit
    u: (Int, Int, Int, Int, Int) -> Unit
    v: (Int, Int, Int, Int, Int) -> Unit
  Rules
    v(!n, !a, !b, !c, !d) -> return(!d) [not(<=(!c, !n))]
    v(!n, !a, !b, !c, !d) -> v(!n, !b, +(!a, !b), +(!c, 1), +(!a, !b)) [<=(!c, !n)]
    u(!n, !a, !b, !c, !d) -> v(!n, !a, !b, 2, !d) [and(not(<(!n, 0)), not(!n = 1))]
    u(!n, !a, !b, !c, !d) -> return(1) [and(not(<(!n, 0)), !n = 1)]
    u(!n, !a, !b, !c, !d) -> return(0) [<(!n, 0)]
    fastfib(!n) -> u(!n, 0, 1, !rnd3, !rnd4)
No termination info given.

Elapsed Time:  42.59 ms