N = int(input())
A = map(int, input().split())

l = list(A)    # リスト化＋昇順ソート
ls =sorted(l)

if N%2 == 1:
    i = N//2
    ans =int(ls[i])

else:
    i = int(N/2)
    ans = (int(ls[i-1]) + int(ls[i]) )/2

print(ans)