def main():
    scores = [int(i) for i in input().split()]
    max_num = max(scores)
    min_num = min(scores)
    scores.remove(max_num)
    scores.remove(min_num)
    ans = sum(scores)/len(scores)
    print("{0:.2f}".format(ans))

if __name__ == '__main__':
    main()