#include <iostream>

using namespace std;

int main() {
    long double a,b;
    cin >> a >> b;
    long double ans = 0;
    long double eps = (b - a) / 1000;
    for (long double i=a; i<b; i+=eps) {
        ans += (b - a) / 1000 * (i-a)*(i-b);
    }

    if (ans < 0) ans *= -1;
    cout << ans << endl;
}