/****************************************************
 * dt03.cpp											*
 *													*
 *  Created on: 2010-11-22							*
 *      Author: Administrator						*
 ****************************************************/
int main()
{
	int a[10];
	int b[10];															//??????
	cin>>a[0]>>b[0];													//??????????
	int i=1,j=1;
	while(true)															//?????????????????????????
	{
		if(a[i-1]%2==0)
		{
			a[i]=a[i-1]/2;
		}
		else
		{
			a[i]=(a[i-1]-1)/2;
		}
		if(a[i]==1)
		{
			break;
		}
		else i++;
	}
	while(true)															//?????????????????????????
	{
		if(b[j-1]%2==0)
		{
			b[j]=b[j-1]/2;
		}
		else
		{
			b[j]=(b[j-1]-1)/2;
		}
		if(b[j]==1)
		{
			break;
		}
		else j++;
	}
	while(i>=0&&j>=0)													//?????????
	{
		if(a[i]==b[j])
		{
			i--;
			j--;
		}
		else
		{
			break;
		}
	}
	cout<<a[i+1];														//???????
	return 0;
}
