N = input()
A = list(map(int, input().split()))

new_num = 0

set_a = set(A)

a_num = {}

for s in set_a:
    a_num[s] = 0

for a in A:
    if a in a_num:
        a_num[a] += 1

for d in a_num.values():
    if d == 1:
        new_num += 1

print(new_num)