# -*- coding: utf-8 -*-

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

dict = {}
for a in A:
    if a in dict:
        dict[a] += 1
    else:
        dict[a] = 1

ans = 0
for key in dict:
    ans += 1 if dict[key]==1 else 0

print(ans)