#include <fstream>
using namespace std;
ifstream f("euclid2.in");
ofstream g("euclid2.out");
int a, b;
int main()
{
	f >> a >> b;
	int r = a % b;
	while (r)
	{
		a = b;
		b = r;
		r = a % b;
	}
	g << b;
}