module Main {

func Apply(x: int, op: func(int) -> int) -> int {
    return op(x);
}

func Double(n: int) -> int {
    return n * 2;
}

func main() -> int {
    let result: int = Apply(5, &Double);
    if result != 10 { return 1; }
    return 0;
}

}
