#include <bits/stdc++.h>

using namespace std;

#define REP(i,n) for(int i=0; i<(int)(n); i++)
#define FOR(i,b,e) for (int i=(int)(b); i<(int)(e); i++)
#define ALL(x) (x).begin(), (x).end()

const double PI = acos(-1);

int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);

  double alpha, beta;
  cin >> alpha >> beta;

  // f(x) = x ^ 2 + b x + c
  double b = - (alpha + beta);
  double c = alpha * beta;

  double ret = 0;
  int N = 1e7;
  for (int i = 1; i < N; i++) {
    double x = alpha + (beta - alpha) / N * i;
    double f = x * x + b * x + c;
    ret += f * (beta - alpha) / N;
  }
  cout << fixed << setprecision(10) << abs(ret) << endl;
  
  return 0;
}