#include<bits/stdc++.h>

using namespace std;
using ll = long long;

ll gcd(ll a,ll b){
    if(b == 0) return a;
    else return gcd(b,a%b);
}

int main(){
    ll a,b;
    cin >> a >> b;
    ll ans = gcd(a,b);

    cout << ans << endl;
    return 0;
}