ước chung lớn nhất

#include <iostream>
using namespace std;
int ucln(int m, int n){
    if(m>n) return ucln(m-n, n);
    if(m<n) return ucln(m, n-m);
    if(m==n) return m;
}
int main(){
    int m, n;
    cin >> m >> n;
    if(ucln(m, n)!=1) cout<<"NO";
    else cout<<"YES";
}