#include <iostream>
#include <fstream>
using namespace std;
ifstream fin("cmmdc.in");
ofstream fout("cmmdc.out");
int a,b;

int main()
{
    fin>>a>>b;
    while(a!=b)
    {
        if (a>b)
            a=a-b;
        else
            b=b-a;
    }
    if(a==1)
        fout<<"0";
    else
        fout<<a;
    fin.close();
    fout.close();
    return 0;
}