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

for i in range(N):
    if len(v) == 1:
        pass
    else:
        if min(v) in v:
            aaa =min(v)
            v.remove(min(v))
        if min(v) in v:
            bbb =min(v)
            v.remove(min(v))
            ccc =(aaa + bbb)/2
            v.append(ccc)
print(v)

