#include <iostream>
#include <fstream>

using namespace std;

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

int main()
{
    int a, b, rest;
    fin>>a>>b;
    while (a!=b){
        if (a>b) a=a-b;
        else b=b-a;
    }if (a==1) fout << "0";
    else fout << a;
    return 0;
}