#include <fstream>
#include <iostream>
#include <cmath>
using namespace std;
int main(void)
{
    long a,b,m,n,r;
    
    fstream fin("cmmdc.in", ios::in);
    fstream fout("cmmdc.out", ios::out);
    fin >> a;
    fin >> b;
    a = labs (a);
    b = labs (b);
    
    m = a;
    n = b;
    do
    {
       r = m % n;
       m = n;
       n = r;
    }
    while (r);
    
    if (m == 1)
    {
        fout << 0;
        fout.close();
        fin.close();
        return 0;
    }
    else /*if (m!=1) */
    {
        fout << m;
        fout.close();
        fin.close();
        return 0;
    }
}