#include <bits/stdc++.h>
#define rep(i,n) for (int i=0; i<(n); ++i)
using namespace std;
typedef long long ll;

int main() {
    double a, b;
    cin >> a >> b;
    
    int N = 1000000;
    double d = (b-a) / N;
    double area = 0;
    for (int i=0; i<N; ++i) {
        double x = a + i * d;
        area += d * abs((x - a) * (x - b));
    }

    printf("%.7f\n", area);
    return 0;
}