/*
 * ????ercha.cpp
 * ?????x,y,?xi.
 * ????: 2012-11-30
 * ??: ?   ?
 */



int main()
{
	int x = 0, y = 0;//?????????
	cin >> x >> y;//??????
	while ( x != y )
	{
		if ( x > y )  x = x/2;//??x>y,??x?????
		else y = y/2;//???y?????
	}
	cout << x << endl;//?????
	return 0;//????
}
