#!/usr/bin/env python
# -*- coding: utf-8 -*-
import collections

N = int(input())
A = list(map(int,input().split()))
count = collections.defaultdict(int)
for a in A:
    count[a] += 1
ans = 0
for key,value in count.items():
    if value == 1:
        ans += 1
print(ans)