#include <iostream>
#include <algorithm>
using namespace std;
int main(){
	int N;
	int A[100002]={};
	cin>>N;
	for(int i=1;i<=N;i++){
		cin>>A[i];
	}
	A[0] = 0;
	A[N+1] = 0;
 	sort(A+1,A+N+1);
 	int res=0;
	for(int i=1;i<=N;i++){
		if(A[i] != A[i-1] && A[i] != A[i+1]){
			res++;
		}
	}
	cout<<res<<endl;
}