#include <bits/stdc++.h>
using namespace std;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);

	int a, b;
    cin >> a >> b;
    double fx = pow(b, 3) / 3 - (a + b) * pow(b, 2) / 2 + a * b * b
                - (pow(a, 3) / 3 - (a + b) * pow(a, 2) / 2 + a * b * a);
    cout << abs(fx) << endl;
}