# -*- coding:utf-8 -*-
if __name__ == '__main__':
    n = int(input())
    an = sorted(map(int, input().split()))
    l = len(an)
    if l % 2 == 0:
        print((an[int(l/2)] + an[int(l/2) - 1]) / 2)
    else:
        print(an[int(l/2)])