def main():
    a, b = map(int, input().split())
    ans = solve(a, b)
    print(ans)

def abs(x):
    return x if x > 0 else - x

def solve(a, b):
    if a == b:
        return 0
    d = 10 ** 4
    dx = (b -a) / d
    ans = 0
    for i in range(d):
        x = a + dx * i
        y = (x - a) * (x - b)
        ans += abs(y * dx)
    return ans

if __name__ == '__main__':
    main()