n = int(input())
a = list(map(int, input().split()))
a.sort()

if n % 2 == 1:
    median = a[n//2]
else:
    median = (a[n//2 - 1] + a[n//2]) / 2

median = float(median)

if median.is_integer():
    print(int(median))
else:
    print("{0:.1f}".format(median))