import sys
input = sys.stdin.buffer.readline

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

N = 10 ** 4
d = (b - a) / float(N)
f = lambda x: (x - a)*(x - b)
S = 0

for i in [a + (x * d) for x in range(0, N + 1)]:
    s = abs(d * f(i))
    S += s
    
print(round(S, 7))