n=int(input())
a = [int(i) for i in input().split()]
cntDic = {}
sa = []
for i in range(-1000, 1001):
    cntDic[str(i)] = 0
for ae in a:
    cntDic[str(ae)] += 1
for i in range(-1000, 1001):
    if cntDic[str(i)] is 0:
        continue
    for cnt in range(cntDic[str(i)]):
        sa.append(i)
if len(sa)%2 is 1:
    print(sa[len(sa)//2])
else:
    print((sa[len(sa)//2]+sa[len(sa)//2-1])/2)