#include <bits/stdc++.h>

using namespace std;

int main(){
    int n;
    cin >> n;
    vector<int> types(n);
    for(int types_i = 0; types_i < n; types_i++){
       cin >> types[types_i];
    }
   for(int types_i = 0; types_i < n; types_i++){
       for(int types_j = types_i+1; types_j < n; types_j++)
       {
       if(types[types_i] == types[types_j])
           cout<<types[types_i];
   }
   }
    // your code goes here
    return 0;
}