#include<iostream>
#include<iomanip>
#include<vector>
#include<string>
#include<cmath>
#define rep(i, start, end) for (int i = (int)start; i < (int)end; ++i)
#define rrep(i, start, end) for (int i = (int)start - 1; i >= (int)end; --i)
#define all(x) (x).begin(), (x).end()
using namespace std;
using ll = long long;
template<typename T> inline bool chmax(T& a, T b) {if (a < b) {a = b; return true;} return 0;}
template<typename T> inline bool chmin(T& a, T b) {if (a > b) {a = b; return true;} return 0;}

double f(double A, double B, double X) {
    return abs((X - A) * (X - B));
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(false);
    double A, B;
    cin >> A >> B;
    int N = 1e5;
    vector<double> X(N);
    X[0] = A;
    rep(i, 1, N) {
        X[i] = X[i - 1] + (B - A) / N;
    }
    double ans = 0;
    rep(i, 0, N) {
        ans += (B - A) * f(A, B, X[i]) / N;
    }
    cout << fixed << setprecision(5) << ans << endl;
    return 0;
}