// Towers of Hanoi in Fun

def hanoi(n: Int, a: Int, b: Int, c: Int) : Void =

  if n != 0 then {

    hanoi(n - 1, a, c, b);

    print_int(a);

    print_char('-'); print_char('>'); // prints out "->"

    print_int(b);

    print_char('\n');

    hanoi(n - 1, c, b, a)

  } else skip;

hanoi(4,1,2,3)