let test =
    let r = ref 1;
    for i from (1) to (5) {
      for i from (1) to (5) {
        r := !r * i
      };
      r := !r * i;
      for i from (1) to (5) {
        r := !r / i
      }
    };
    print_string ("This test is ");
    print_string (if (!r =? 120) then { "OK!\n" } else { "KO!\n" })