#include <iostream>
#include <algorithm>
#include <string>
#include <vector>

using namespace std;
using ll = long long;
#define rep(i,n) for(int i = 0; i < (int)(n); i++)
#define all(c) begin(c), end(c)

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

int main() {
	ll A, B;
	cin >> A >> B;
	cout << gcd(A + B, A) << endl;
	return 0;
}