N = list(input())
value = sorted(list(map(int,input().split()))) 

if len(value)%2 != 0:
    i = (len(value)+1)//2
    cv = value[i-1]
else:
    pi = len(value)//2
    ai = pi
    cv = (value[pi-1]+value[ai])/2
    
print(cv)