#include <bits/stdc++.h>

#define rep(X,N) for(ll X = 0; X < (N); X++)
#define PI (acos(-1.0))
#define pback push_back
#define mpair make_pair
#define MODN 1000000007
#define ALL(V) (V).begin(),(V).end()
#define INT_MAX_HALF (INT_MAX / 2)
#define EPS (1e-10)

using namespace std;
typedef long long ll;

double f(double a, double b, double x){
    return 1.0 / 3 * pow(x, 3.0) - (a + b) / 2 * pow(x, 2.0) + a * b * x;
}

int main(){

    double a,b;
    cin >> a >> b;

    cout << setprecision(12) << abs(f(a, b, a) - f(a, b, b)) << endl;
}