#define _USE_MATH_DEFINES #include <cmath> #include <cstdio> #include <vector> #include <iostream> #include <algorithm> #include <string> #include<math.h> #include<iomanip> #include<stdio.h> #include <stdlib.h> #include<stdio.h> #include <queue> #include<map> #include <fstream> #include <sstream> #include<set> #include<stack> #include<time.h> #include <sys/types.h> #include <tuple> #include <numeric> #include <iterator> typedef long long int ll; //#include<bits/stdc++.h> using namespace std; int main() { int Q; Q = 1; //cin >> Q; while (Q--) { int n; cin >> n; vector<int>a(n); map<int, int>t; for (int i = 0; i < n; i++) { cin >> a[i]; t[a[i]]++; } int ans = 0; for (int i = 0; i < n ; i++) { if (t[a[i]] == 1)ans++; t[a[i]] = 0; } cout << ans; } return 0; }