/*
Jackson Simoneau
SI@UCF 2026 - Intro to Competitive Programming
Contest 2

Solution to Diagonal Cut: https://open.kattis.com/problems/diagonalcut
*/

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

int main() {
    ll m, n;
    cin >> m >> n;
    ll res = __gcd(m, n);

    if(m/res % 2 && n/res % 2) cout << res << endl;
    else cout << 0 << endl;    
}