//inlclude前用define 
#define _USE_MATH_DEFINES

//include
#include<iostream>
#include<string>
#include<algorithm>
#include<vector>
#include<cmath>
#include<cstdio>
#include<type_traits>
#include<numeric>
#include<limits>
#include<iomanip>
using namespace std;
//typedef
typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<char> VC;

//grobal変数


int main() {
	int n;
	cin >> n;
	VI a(n+2);
	for (int i = 1; i <= n; i++) cin >> a[i];

	sort(a.begin()+1, a.begin()+n+1);
	/*for (int i = 1; i <= n; i++) {
		cout << a[i] << " ";
	}*/
	int cnt = 0;
	for (int i = 1; i <= n; i++) {
		if (a[i] != a[i - 1] && a[i] != a[i + 1]) {
			cnt++;
		}
	}

	//cout << "\n";
	cout << cnt << endl;
	return 0;
}