N = int(input())
vs = list(map(int, input().split()))

vs.sort(reverse=True)
print(vs)

if N == 2:
    print((vs[0] + vs[1]) / 2)
    exit()

x = (vs[0] + vs[1])/2
for i in range(1, N):
    x = (x + vs[i]) / 2

print(x)
