fn gcd(a: i32, b: i32) -> i32 {
    let mut max = a.max(b);
    let mut min = a.min(b);
    loop {
        let res = max % min;
        if res == 0 { return min; }
        max = min;
        min = res;
    }
}

fn main() {
    let n = 20;
    let mut p = 1;

    for k in 1..=n {
        let q = gcd(p, k);
        let m = k / q;
        p *= m;
        println!("{} -> {}", k, p);
    }

}