package main

import "fmt"

func main() {
	var a, b, ans, N float64
	fmt.Scan(&a, &b)
	N = 10000.0
	if a != 0 && b != 0 {
		for i := 1; i <= int(N); i++ {
			x := a + (b-a)/N*float64(i)
			ans += (b - a) / N * abs((x-a)*(x-b))
		}
	}
	fmt.Println(ans)
}
func abs(a float64) float64 {
	if a < 0 {
		return -a
	}
	return a
}