N = int(input())
v = list(map(int,input().split()))
v_new = 0
for i in range(N-1):
    x = max(v)
    y = min(v)
    v_new = (x+y)/2
    v.append(v_new)
    v.remove(x)
    v.remove(y)
    v_new = 0
print(v)