#include <iostream>
#include <sstream>
#include <math.h>
#include <stack>
#include <set>
#include <algorithm>
#include <string>
#include <queue>
#include <stack>
#include <map>
#include <cstdio>
#include <vector>
using namespace std;

#define INF (1 << 30)
#define INFLL (1LL << 60)

int main() {
	int n,A[100000];
	int ans = 0;
	cin >> n;
	for(int i = 0;i < n;i++){
		cin >> A[i];
	}
	sort(A,A+n);
	for(int i = 0;i < n;i++){
		if(i == 0 && A[i] != A[i+1]) ans++;
		else if(i == n - 1 && A[i] != A[i-1]) ans++;
		else if(A[i] != A[i+1] && A[i] != A[i-1]) ans++;
	}
	cout << ans << endl;
	return 0;
}