#include <iostream>
#include "queue.h"

using namespace std;

void result(queue *&h, queue *&t, queue *&hr, queue *&tr)
{
    int prev;
    prev = pop(h, t);
    push(hr, tr, prev);

    while (h)
    {
        int cur = pop(h, t);
        if (cur != prev)
        {
            prev = cur;
            push(hr, tr, cur);
        }
    }
}

int main()
{
    int n;
    cout << "n = ";
    cin >> n;

    queue *head = NULL;
    queue *tail = NULL;
    char x;
    for (int i = 0; i < n; i++)
    {
        cin >> x;
        push(head, tail, int(x));
    }

    queue *head_res = NULL;
    queue *tail_res = NULL;

    result(head, tail, head_res, tail_res);
    while (head_res)
        cout << char(pop(head_res, tail_res)) << " ";
    cout << endl;

    return 0;

}