
N=int(input())

A=input().split()
B=[0]*N

for i in range(len(A)):
    B[i]=int(A[i])

B.sort()
print(B)
B[0]=B[0]/(2**(N-1))

for i in range(len(B)-1):
    j=i+1
    B[j]=B[j]/(2**(N-j))

print(sum(B))