YES
LCTRS
  Theories
    Core, Ints
  Signature
    fib: Int -> Int
  Rules
    fib(!x) -> +(fib(-(!x, 1)), fib(-(!x, 2))) [>=(-(!x, 2), 0)]
    fib(1) -> 1
    fib(!x) -> 0 [<=(!x, 0)]
RPO with precedence:
  {fib >= <= 2 1 0 - +}

Elapsed Time:  38.47 ms