package usacoCAMP;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.SortedSet;
import java.util.StringTokenizer;
import java.util.TreeSet;

public class similarcows {

    public static void main(String[] args) throws Exception {
        BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
        PrintWriter w = new PrintWriter(System.out);

        int n = Integer.parseInt(r.readLine());

        TreeSet<String> cows = new TreeSet<String>();

        for (int i = 0; i < n; i++) {
            StringTokenizer st = new StringTokenizer(r.readLine());
            String query = st.nextToken();

            if (query.equals("BUY")) {
                cows.add(st.nextToken());
            } else if (query.equals("SELL")) {
                String first = st.nextToken();
                String second = st.nextToken();

                SortedSet<String> ans = cows.subSet(first, true, second, true);

                ArrayList<String> test = new ArrayList<String>();
                Iterator<String> j = ans.iterator();
                while (j.hasNext()) {
                    test.add(j.next());
                }

                for (int k = 0; k < test.size(); k++) {
                    cows.remove(test.get(k));
                }
                //cows.removeAll(ans);
            }
        }

        Iterator<String> i = cows.iterator();

        while (i.hasNext()) {
            w.println(i.next());
        }
        w.flush();
    }

}