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