#include <iostream>
#include <vector>

using namespace std;

long long gcd(long long A, long long B){
    if(B == 0) return A;
    else return gcd(B, A % B);
}

int main(){
    long long A, B;
    cin >> A >> B;

    long long ans = A + B;
    ans = gcd(ans, A);    
    ans = gcd(ans, B);

    cout << ans << endl;
}