# import sys

# sys.setrecursionlimit(10 ** 6)

int1 = lambda x: int(x) - 1

def II(): return int(eval(input()))



def MI(): return list(map(int, input().split()))

def MI1(): return list(map(int1, input().split()))



def LI(): return list(map(int, input().split()))

def LLI(rows_number): return [LI() for _ in range(rows_number)]



from collections import deque



def solve():

    n = II()

    V = sorted(LI())

    ans = V[0]

    for i in range(1, n):

        ans = (ans + V[i]) / 2

    print(ans)



if __name__ == '__main__':

    solve()

# import sys

# sys.setrecursionlimit(10 ** 6)

int1 = lambda x: int(x) - 1

def II(): return int(eval(input()))



def MI(): return list(map(int, input().split()))

def MI1(): return list(map(int1, input().split()))



def LI(): return list(map(int, input().split()))

def LLI(rows_number): return [LI() for _ in range(rows_number)]



def solve():

    n = II()

    V = sorted(LI())

    ans = V[0]

    for i in range(1, n):

        ans = (ans + V[i]) / 2

    print(ans)



if __name__ == '__main__':

    solve()

# import sys
# sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1


def II():
    return int(eval(input()))


def MI():
    return list(map(int, input().split()))


def MI1():
    return list(map(int1, input().split()))


def LI():
    return list(map(int, input().split()))


def LLI(rows_number):
    return [LI() for _ in range(rows_number)]


from collections import deque


def solve():
    n = II()
    V = sorted(LI())
    ans = V[0]
    for i in range(1, n):
        ans = (ans + V[i]) / 2
    print(ans)


if __name__ == "__main__":
    solve()

# import sys
# sys.setrecursionlimit(10 ** 6)
int1 = lambda x: int(x) - 1


def II():
    return int(eval(input()))


def MI():
    return list(map(int, input().split()))


def MI1():
    return list(map(int1, input().split()))


def LI():
    return list(map(int, input().split()))


def LLI(rows_number):
    return [LI() for _ in range(rows_number)]


def solve():
    n = II()
    V = sorted(LI())
    ans = V[0]
    for i in range(1, n):
        ans = (ans + V[i]) / 2
    print(ans)


if __name__ == "__main__":
    solve()

-from collections import deque - -