#include <iostream>
#include <queue>
#include <unordered_map>
#include <algorithm>
using namespace std;
//Here I am making one additional field in node called height
//which will store left and right ht of tree to the left ht becomes negative
//form the root and right height becomes positive

class node{
  public :
    int data ;
    node *left, *right;
    int level;
    node(int d){
        data = d;
        left = right = NULL;
        level = 0;
    }

};

node *build(){
    int d;
    cin>>d;
    node* root = NULL;
    if(d != -1){
        root = new node(d);
        queue<node*> q;
        q.push(root);
        while(!q.empty()){
            node *f = q.front();
            int d1, d2;
            cin>>d1>>d2;
            if(d1 != -1){
                f->left = new node(d1);
                f->left->level = f->level - 1;
                q.push(f->left);
            }
            if(d2 != -1){
                f->right = new node(d2);
                f->right->level = f->level + 1;
                q.push(f->right);
            }
        }
    }
    return root;
}

int height(node* root){
    if(root == NULL){
        return 0;
    }
    int l = height(root->left);
    int r = height(root->right);
    return max(l, r) + 1;

}

void topView(node* root, unordered_map<int, int> &m){
    if(m[root->level] != -1 || root == NULL)
        return;
    m[root->level] = root->data;
    topView(root-> left, m);
    topView(root-> right, m);

}

int main(){
    node *root = build();
    //creating unordered map storing tree information
    unordered_map <int, int> m;
    int limit = height(root);
    for(int i = -limit; i <= limit ; i++)
        m[i] = -1;
    topView(root, m);
    for(auto p : m){
        cout<<p.second<<" ";
    }
    return 0;
}