#include <bits/stdc++.h>
using namespace std::literals::string_literals;
using i64 = std::int_fast64_t;
using std::cout;
using std::cerr;
using std::endl;
using std::cin;

template<typename T>
std::vector<T> make_v(size_t a){return std::vector<T>(a);}

template<typename T,typename... Ts>
auto make_v(size_t a,Ts... ts){
  return std::vector<decltype(make_v<T>(ts...))>(a,make_v<T>(ts...));
}

int main() {
	int a, b; scanf("%d%d", &a, &b);

	auto calc = [&](long double x) {
		return x * x * x / 3. - x * x * (a + b) / 2. + x * a * b;
	};
	
	printf("%.12Lf\n", std::abs(calc(b) - calc(a)));
	return 0;
}