#include <bits/stdc++.h>   using namespace std;   string ans;   map<pair<string, int>, int> dp;   bool check(string second) {     int mul = 1;     int num = 0;     int i = second.size() - 1;     num = num + ((second[i] -  0 ) * 1) % 8;     i--;     if (second.size() > 1) {       num = num + ((second[i] -  0 ) * 10) % 8;     }     i--;     if (second.size() > 2) {       num = num + ((second[i] -  0 ) * 100) % 8;     }     if (num % 8 == 0) {       ans = second;       return true;     } else {       return false;     }   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(0);     cout.tie(0);     int n;     cin >> n;     int a[n];     vector<int> v[1001];     for (int i = 0; i < n; i++) {       cin >> a[i];       v[a[i]].push_back(i);     }     vector<int> ans;     for (int i = 1; i < 1001; i++) {       if (v[i].size() > 0) ans.push_back(v[i][v[i].size() - 1]);     }     sort(ans.begin(), ans.end());     cout << ans.size() << endl;     for (int i = 0; i < ans.size(); i++) {       cout << a[ans[i]] <<    ;     }     return 0;   }   