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

    return 0;
}