#include <bits/stdc++.h>
using namespace std;

int GCD( const int X, const int Y )
{
int s;
int t;

	s = X;
	t = Y;
	while( true )
	{
		s %= t;
		if( s == 0 ) return t;

		t %= s;
		if( t == 0 ) return s;
	}

	return 0;
}

int main()
{
int N;
int M;

	cin >> N;
	cin >> M;
	cout << GCD( N, M ) << endl;

	return 0;
}