from functools import reduce





def main():

    eval(input())

    v = sorted(map(int, input().split()))

    print((reduce(lambda x, y: (x + y) * 0.5, v)))





main()

def main():

    eval(input())

    v = sorted(map(int, input().split()))

    ans = v[0]

    for i in v[1:]:

        ans = (ans + i) * 0.5

    print(ans)

    return





main()

from functools import reduce


def main():
    eval(input())
    v = sorted(map(int, input().split()))
    print((reduce(lambda x, y: (x + y) * 0.5, v)))


main()

def main():
    eval(input())
    v = sorted(map(int, input().split()))
    ans = v[0]
    for i in v[1:]:
        ans = (ans + i) * 0.5
    print(ans)
    return


main()

-from functools import reduce - - -    print((reduce(lambda x, y: (x + y) * 0.5, v))) +    ans = v[0] +    for i in v[1:]: +        ans = (ans + i) * 0.5 +    print(ans) +    return