//自己重新写了一个Java的，按Ctrl-z可以结束，基本思路是用位图来实现快速发现根节点。然后
//多叉树的存储为链表结构
import java.io.*;
import java.util.*;

class Node {
	int val;
	Node child;
	Node next;

	Node(int v) {
		val = v;
		child = null;
		next = null;
	}
}

public class Build {
	public static void myTraverse(Node root){
		Node p = root;
		
		//hierarchy traverse
		while(p != null){
			//cur root
			System.out.print(p.val + " ");
			
			//siblings
			while(p.next != null){
				System.out.print(p.next.val + " ");
				p = p.next;
			}
			
			//child
			if(p.child != null){
				p = p.child;
			}
			else{
				break;
			}
		}
	}
	public static void main(String args[]) {
		Scanner in = new Scanner(System.in);

		//bitmap 
		//save every node 
		//find element quickly
		Node[] arr = new Node[101];
		for (int i = 0; i < 101; i++) {
			arr[i] = null;
		}

		Node coreRoot = null;
		int count = 0;
		
		//Ctrl-z end input
		while (in.hasNextLine()) {
			String line = in.nextLine();
			
			String strs[] = line.split("\\s+");
			
			Node root = null;
			for (int i = 0; i < strs.length; i++) {
				int num = Integer.valueOf(strs[i]);

				//cur root
				if (i == 0) {
					if (arr[num] == null) {
						Node temp = new Node(num);
						arr[num] = temp;
					}
					root = arr[num];

				}
				//this level siblings
				else {
					Node temp = null;
					if (arr[num] == null) {
						temp = new Node(num);
						arr[num] = temp;
					}
					temp = arr[num];

					Node p = root;
					while (p.next != null) {
						p = p.next;
					}
					p.next = temp;
				}
			}
			//core root
			if (count == 0) {
				coreRoot = root;
			}
			count += 1;
		}
		myTraverse(coreRoot);
	}
}