#include <iostream>
#include <fstream>
using namespace std;
ifstream f("cmmdc.in");
ofstream g("cmmdc.out");



int main()
{
   long long a,b;

   f>>a>>b;

   while (a!=b){
    if (a>b){
        a=a-b;
    }else b=b-a;
   }
    if (a==1 && b==1)
        g<<"0";
    else {
    if (a>b)
    g<<a;
   else g<<b;
    }
    return 0;
}