#include <fstream>
using namespace std;

fstream fin("cmmdc.in");
ofstream fout("cmmdc.out");
int prim (int a, int b) {
  while (a != b)
  {
    if(a > b)
      a -= b;
    else 
      b -= a;
  }
  return a;
}
int main() {
  int a, b;
  fin >> a >> b;
  if (prim(a,b) == 1)
    fout << 0;
  else
  {
    while (b != 0){
      int r = a % b;
      a = b;
      b = r;
    }
    fout << a;
  }
  return 0;
}