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


a, b = map(int, input().split())
# 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)