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

ll gcd(ll a, ll b);

int main() {

    // Read in stuff.
    ll n, m;
    cin >> n >> m;
    ll div = gcd(n,m);
    n /= div;
    m /= div;

    if (n%2 == m%2)
        cout << div << endl;
    else
        cout << 0 << endl;
    return 0;
}

ll gcd(ll a, ll b) {
    return b == 0 ? a : gcd(b, a%b);
}