#include<fstream>
#include <iostream>

using namespace std;

int a, b, x;

int main() {
    ifstream fin(euclid2.in);
    ofstream fout(euclid2.out);
    fin>>a>>b;
    while(a)
    {
        x=a%b;
        a=b;
        b=x;
    }
    fout<<b;
}