#include <cstdio>

using namespace std;

int main()
{
    freopen("euclid2.in","r",stdin);
    freopen("euclid2.out","w",stdout);
int a,b,r;
  scanf( "%d%d", &a, &b );
  while ( b > 0 ) {
    r = a % b;
    a = b;
    b = r;
  }
  if(a==1)
        printf("0\n");
    else
        printf( "%d", a );

  return 0;
}