GCD short

#include <bits/stdc++.h>
using namespace std;

#define int long long
#define double long double
#define pb push_back

int GCD(int a , int b){
    while(a && b){
        if(a > b)
            a %= b;
        else
            b %= a;
    }
    return a + b;
}

int gcd(int a , int b){
    if(!a || !b)
        return a + b;
    return gcd(b , a % b);
}

signed main()
{
    int a , b;
    cin >> a >> b;
    cout << gcd(a , b) << endl;
}