#include <iostream>
#include <fstream>

using namespace std;

int main()
{
    ifstream fin("cmmdc.in");
    ofstream fout("cmmdc.out");
    int a,b,rest;
    fin>>a>>b;
    while(b)
    {
        rest=a%b;
        a=b;
        b=rest;
    }
    if(a!=1)
        fout<<a;
    else
        fout<<"0";
    return 0;
}