#include<iostream>
#include<fstream>
using namespace std;

ifstream fin("cmmdc.in");
ofstream fout("cmmdc.out");

int main()
   {
     int a,b;
   fin >> a >> b;

    while (a!=b)
         {
          if (a>b)
            a-=b;

          else
            b-=a;
     }

  if (a<=1 || b<=1)
            fout << 0;
  else
            fout << a;
   return 0;
}