#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;
}