#include <iostream>
#include <fstream>

using namespace std;

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

int a,b;

int cmmdc(int a, int b)
{
    if(b==0)
        return a;
    else
        return cmmdc(b,a%b);
}

int main()
{
    fin>>a;
    fin>>b;
    int c=cmmdc(a,b);
    if(c==1)
        fout<<0;
    else
        fout<<c;
    return 0;
}