#include <iostream>
using namespace std;
int f(int n, int p)
{
int res = 0;
while (n) res += n / p, n /= p;
return res;
}
int main()
{
int n, m;
while (cin >> n >> m, n)
cout << f(n, 2) - f(n - m, 2) << '\n';
return 0;
}