#include<iostream>
using namespace std;
int k;
int fen(int n)
{
	if((n - k) % 2 != 0 && (n - k) < 0)return 1;
	else
	{
		int n1 = (n - k) / 2;
		int n2 = (n + k) / 2;
		fen(n1);
		fen(n2);
		return n1 + n2;
	}
}
int main()
{
	int n;
	cin >> n >> k;
	cout << fen(n) << endl;
	return 0;
}