import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;

public class Main {

    public static void BFS(HashMap<String, Vertax> graph, String vertax) {
        Queue<String> queue = new LinkedList<String>();
        queue.add(vertax);
        graph.get(vertax).flag = true;

        while (!queue.isEmpty()) {
            String value = queue.poll();
            System.out.print(value + " ");
            Vertax v = graph.get(value);
            Iterator<String> iter = v.next.iterator();
            while (iter.hasNext()) {
                String next_value = iter.next();
                if (graph.get(next_value).flag == false) {
                    queue.add(next_value);
                    graph.get(next_value).flag = true;
                }
            }
        }
    }

    public static void main(String[] args) {
        HashMap<String, Vertax> graph = new HashMap<String, Vertax>();

        try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
            String line;
            while ((line = br.readLine()) != null) {
                String[] tokens = line.split(" ");
                String value = tokens[0];
                Vertax vertax = new Vertax(value);
                graph.put(value, vertax);
                for (int i = 1; i < tokens.length; i++) {
                    vertax.next.add(tokens[i]);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        BFS(graph, "A");
    }

}

class Vertax {
    String value;
    boolean flag;
    LinkedList<String> next;

    public Vertax(String value) {
        this.value = value;
        this.flag = false;
        next = new LinkedList<String>();
    }

}

/* inputs on console of eclipse
A B S
B A
C D E F S
D C
E C H
F C G
G S H
H E G
S A C G
*/