#include <iostream>
using namespace std;

int gcd_recur(int n1, int n2)
{
	if (n1 == n2)
	{
		return n1;
	}
	
	if (n1 > n2)
	{
		return gcd_recur(n1-n2, n2);
	}
	else
	{
		return gcd_recur(n1, n2-n1);
	}
}

int main()
{
	int a, b;
	cin >> a >> b;

	cout << gcd_recur(a, b);
}