#include <iostream>
#include <fstream>

using namespace std;

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

int main()
{
    long long a, b, r;
    fin >> a >> b;
    while(b != 0)
    {
        r = a % b;
        a = b;
        b = r;
    }
    if(a == 1) fout << 0;
    else fout << a;
}