#!/usr/bin/env python3

import scipy.integrate


def compute_area(a, b):
    res = scipy.integrate.quad(lambda x: -(x - a) * (x - b), a, b)
    return res[0]


def main():
    a, b = (int(z) for z in input().split())
    area = compute_area(a, b)
    print("{:.12f}".format(area))


if __name__ == "__main__":
    main()