#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;

    return 0;
}