int common(int x,int y);
int main()
{
	int x,y;
	scanf("%d %d",&x,&y);
	int result=common(x,y);
	printf("%d\n",result);
	return 0;
}
int common(int x,int y)
{
	if(x==y)
	{
		return x;
	}
	else if(x>y)
	{
		return common(x/2,y);
	}
	else
	{
		return common(x,y/2);
	}
}
