import java.util.*;
public class Main {
static Scanner scn = new Scanner(System.in);
public static void main(String[] args) {
Main m = new Main();
BinaryTree bt = m.new BinaryTree();
bt.levelOrderZZ();
}
private class BinaryTree {
private class Node {
int data;
Node left;
Node right;
}
private Node root;
private int size;
public BinaryTree() {
this.root = this.takeInput(null, false);
}
public Node takeInput(Node parent, boolean ilc) {
int cdata = scn.nextInt();
Node child = new Node();
child.data = cdata;
this.size++;
// left
boolean hlc = scn.nextBoolean();
if (hlc) {
child.left = this.takeInput(child, true);
}
// right
boolean hrc = scn.nextBoolean();
if (hrc) {
child.right = this.takeInput(child, false);
}
// return
return child;
}
public void levelOrderZZ() {
levelOrderZZ(this.root,0);
}
private void levelOrderZZ(Node node,int k){
LinkedList<Node> queue = new LinkedList<>();
queue.addFirst(node);
while(!queue.isEmpty()){
Node rv = queue.removeFirst();
System.out.print(rv.data+ " ");
if(k%2==0){
if(rv.left!=null){
queue.addLast(rv.left);
}
if(rv.right!=null){
queue.addLast(rv.right);
}
k=k+1;
}else{
if(rv.right!=null){
queue.addLast(rv.right);
}
if(rv.left!=null){
queue.addLast(rv.left);
}
k=k+1;
}
}
}
}
}