# def f(x):
#     return abs((x - a) * (x - b))

a, b = map(int, input().split())
print((b - a)**3 / 6)
# # 底辺
# if a == b:
#     print(0)
#     exit()
# n = (b - a) / 10**4
# now = a
# ans = 0
# while (now <= b):
#     ans += n * f(now)
#     now += n
# print(ans)