#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
#include<queue>
#include<map>
using namespace std;
class Node
{
public:
int left;
int right;
int hd;
int data;
Node(int data, int left, int right): data(data),right(right),left(left){}
};
vector<Node> v;
void topview(Node root)
{
if(root.data==-1) return;
queue<Node>q;
map<int,int> m;
int hd=0;
root.hd=hd;
q.push(root);
while(q.size())
{
hd=root.hd;
if(m.count(hd)==0) m[hd]=root.data;
if(root.left!=-1)
{
v[root.left].hd=hd-1;
q.push(v[root.left]);
}
if(root.right!=-1)
{
v[root.right].hd=hd+1;
q.push(v[root.right]);
}
q.pop();
root=q.front();
}
for(auto i=m.begin();i!=m.end();i++)
{
cout<<i->second<<" ";
}
}
int main() {
/* Enter your code here. Read input from STDIN. Print output to STDOUT */
int n,a,b;
cin>>n;
for(int i=0;i<n;i++){
cin>>a>>b;
Node curr(i,a,b);
v.push_back(curr);
}
topview(v[0]);
return 0;
}
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