#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 = a - b;
  }
  if (b > a) {
   b = b - a;
  }
 }
 if (a == 1) {
  fout << 0;
 } else {
  fout << a;
 }
 return 0;
}