#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("cmmdc.in");
ofstream fout("cmmdc.out");
int main()
{
    int a,b;
    fin>>a>>b;
    while (a!=b)
    {
        if (a>b)
            {
                a=a-b;
            }
        else
            {
                b=b-a;
            }
    }
    if (b==1)
    {
        fout<<0;
    }
    else
        fout<<b;
    return 0;
}