#include <list>
#include <iostream>
#include <unordered_map>
#include <set>
class problem
{
public:
  std::list<int> input_list;
  problem();
  void solution();
};

problem::problem()
{
    int nr_of_elements, buffer;
    std::cout << "Number of elements: \n";
    std::cin >> nr_of_elements;

    for(int i = 0; i < nr_of_elements; ++i)
    {
      std::cin >> buffer;
      input_list.push_back(buffer);
    }
}

void problem::solution()
{
    std::set<int> temp_Set;
    for (auto iterator = input_list.begin(); iterator != input_list.end(); ++iterator)
    {
      if(temp_Set.find(*iterator) ==  temp_Set.end())
        temp_Set.insert(*iterator);
      else
        input_list.erase(iterator);
    }
    for (auto iterator = input_list.begin(); iterator != input_list.end(); ++iterator)
    {
      std::cout << *iterator;
    }
}

int main()
{
  problem solved;
  solved.solution();
}