Distinct Numbers

1#include<bits/stdc++.h>
2using namespace std;
3#define int long long
4signed main(){
5  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
6  int n; cin>>n;
7  map<int,bool> mp;
8  while(n--){
9    int e; cin>>e;
10    mp[e]=1;
11  }
12  cout<<(int)mp.size()<<'\n';
13  return 0;
14}