#include <fstream>

using namespace std;

int main()
{
 int a, b;

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

 fin >> a >> b;

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

 fout.close();
 fin.close();

 return 0;
}