def main():
    p, q, r = map(int, input().split())

    a = p / (p + q + r)
    b = q / (p + q + r)
    c = r / (p + q + r)

    print(max(a, b, c, 1 - a, 1 - b, 1 - c))


if __name__ == "__main__":
    main()