#include <bits/stdc++.h>
#define rep(i,n) for (int i = 0; i < n; ++i)
#define ALL(c) (c).begin(), (c).end()
#define SUM(x) std::accumulate(ALL(x), 0LL)
#define MIN(v) *std::min_element(v.begin(), v.end())
#define MAX(v) *std::max_element(v.begin(), v.end())
#define EXIST(v, x) (std::find(v.begin(), v.end(), x) != v.end())
using namespace std;

typedef long long ll;

template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }
const int INF = 1e9;
const long long INFL = 1LL<<60;

double fx(double a, double b, double x) {
  return (x * x * x) / 3 - ((a + b) / 2.0) * x * x + a * b * x;
}

int main()
{
  int a, b;
  cin >> a >> b;

  double ans = abs(fx(a, b, b) - fx(a, b, a));

  cout << ans << endl;

  return 0;
}