#include <iostream>
using namespace std;
using ll = long long;

int main(void) {
	ll N, K;	cin >> N >> K;

	ll ans = 0;
	ll R = N - K;

	while (N) {
		N >>= 1;
		ans += N;
	}

	while (K) {
		K >>= 1;
		ans -= K;
	}

	while (R) {
		R >>= 1;
		ans -= R;
	}

	cout << ans << endl;
	return 0;
}