def cumsum(n, A):
    s = [0] * (n + 1)
    s[0] = A[0]
    for i in range(len(A)):
        s[i + 1] = (s[i] + A[i]) / 2
    return s


n = int(input())
v = sorted(list(map(int, input().split())))
for i in range(n - 1):
    s = cumsum(n, v)
print(s[-1])

9850a4b2afbfa0efacd6ccacdd6e368ab01cbecd
<mask token>

def cumsum(n, A):
    s = [0] * (n + 1)
    s[0] = A[0]
    for i in range(len(A)):
        s[i + 1] = (s[i] + A[i]) / 2
    return s


<mask token>

def cumsum(n, A):
    s = [0] * (n + 1)
    s[0] = A[0]
    for i in range(len(A)):
        s[i + 1] = (s[i] + A[i]) / 2
    return s


<mask token>
for i in range(n - 1):
    s = cumsum(n, v)
print(s[-1])

def cumsum(n, A):
    s = [0] * (n + 1)
    s[0] = A[0]
    for i in range(len(A)):
        s[i + 1] = (s[i] + A[i]) / 2
    return s


n = int(input())
v = sorted(list(map(int, input().split())))
for i in range(n - 1):
    s = cumsum(n, v)
print(s[-1])
