// https://dashoj.com/p/92
#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

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

int main() {
	ll a, b;
	cin >> a >> b;
	cout << gcd(a, b) << endl;
	return 0;
}