#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(b)
    {
        r=a%b;
        a=b;
        b=r;
    }
    if(a==1)
        fout<<0;
    else
        fout<<a;
    return 0;
}