int main()
{
	int f(int x,int y);
	int x,y,i,j,k,l;
	scanf("%d%d",&x,&y);
	l=f(x,y);
	printf("%d",l);
	scanf("%d",&j);
	return 0;
}
int f(int x,int y)
{
	int a;
	if(x==1||y==1) a=1;
	else if(x%2==0&&y%2==1&&x+1==y) a=x/2;
	else if(x==y) a=x;
	else if(x>y) a=f(x/2,y);
	else a=f(x,y/2);
	return a;
}
