#coding=UTF-8

N=int(input())
mojir=input()
hyo=mojir.split(' ')
A=[int(mono) for mono in hyo]

kireiA=sorted(A)

if N%2 == 0:
    lowmed=kireiA[N//2]
    himed=kireiA[N//2-1]
    print((lowmed+himed)/2)
else:
    print(kireiA[N//2])#3なら[1]番目(0-2)
#実はバッテリー付属案件だったでござる