#include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define int long long #define endl '\n' #define INF 1000000000000000000 #define EPS 1e-10 #define PI 3.141592653589793238 #define all(a) a.begin(),a.end() #define rep(i, n) for (int i = 0; i < (n); i++) #define pb push_back #define double long double using namespace std; typedef long long ll; typedef pair P; typedef pair PP; typedef complex com; template bool chmax(T &a, const S &b) { if (a < b) { a = b; return 1; } return 0; } template bool chmin(T &a, const S &b) { if (a > b) { a = b; return 1; } return 0; } ll gcd(ll n, ll m) { return (m ? gcd(m, n%m) : n); } ll lcm(ll n, ll m) { return n / gcd(n, m)*m; } signed main() { cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); //modcalc(); double a, b; cin >> a >> b; cout << (b - a)*(b - a)*(b - a) / 6 << endl; }