#include<iostream>
#include<map>
#include<vector>
#include <algorithm>
#include<math.h>
#include <iomanip>
#include<set>
#include <numeric>
using namespace std;


int main()
{
    double a, b, sum1;
    cin >> a >> b;
    for (double i = a; i < b; i += 0.001){
        sum1 += (abs((i-a)*(i-b)) + abs((i+0.01-a)*(i+0.01-b))) * 0.001/2;
    }
    cout << sum1 << endl;
}