#include <algorithm>
#include <array>
#include <cmath>
#include <cstdio>
#include <deque>
#include <iomanip>
#include <iostream>
#include <numeric>
#include <optional>
#include <queue>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>

using namespace std;

int main() {
    int32_t a, b;
    cin >> a >> b;
    double ans = 0;
    const auto N = int32_t(1e6);
    auto f = [&](double x) { return (x - a) * (x - b); };
    for (auto i = 0; i < N; ++i) {
        double d = double(b - a) / N;
        double s = d * abs(f(a + d * i));
        ans += s;
    }
    printf("%.9f\n", ans);
    return 0;
}