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

int main() {
 int a, b;
 ifstream f("cmmdc.in");
 ofstream g("cmmdc.out");
 f >> a;
 f >> b;


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

}