#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 (a==1)
        fout << 0;
    else fout << a;
}