int main()
{
	int x,y;    //????x?y???????
	cin>>x>>y;    //??x?y
	void commoninteger(int x,int y);   //????commoninteger
	commoninteger(x,y);    //????commoninteger?????
	return 0;
}

void commoninteger(int x,int y)   //????commoninterger??????x?y???????????
{
	if(x==y)      //??x=y?????????x????
		cout<<x;
	else {
		if(x>y)      //??x>y???x??2???????commoninteger??????y??2???????commoninteger??
			commoninteger(x/2,y);
			else commoninteger(x,y/2);
	}
}