#include <fstream>
using namespace std;

ifstream fin("euclid2.in");
ofstream fout("euclid2.out");

int x,y;

int gcd(int a, int b)
{
    if (!b)
        if(x%a+y%a==0)
            return 0;
        else
            return a;
    else
        return gcd(b, a%b);
}

int main() {
    fin>>x>>y;
    fout<<gcd(x,y);
    return 0;
}