n = int(input()) l = list(map(int,input().split())) for i in range(n-1): for j in range(n-i-1): if l[j] > l[j+1]: tem = l[j] l[j] = l[j+1] l[j+1] = tem if n % 2 == 0: print((l[n//2-1]+l[n//2])/2) else: print(l[n-1//2])