N = int(input())
listA = [int(i) for i in input().split()]

listA_uq = []
for _ in listA:
    if not _ in listA_uq:
        listA_uq.append(_)

count = 0
for _ in listA_uq:
    if listA.count(_) == 1:
        count += 1

print(count)