Shared code

/* 777 */
#include "bits/stdc++.h"
using namespace std;

#define int long long 

// const int MOD=1e9+7;
vector<int>vec;

void solve(){
	int n,x;cin>>n;
	set<int>s;
	while(n--){
		cin>>x;
		s.insert(x);
	}
	cout<<s.size()<<'\n';
}

signed main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	solve();
}