rt B3642

#include<bits/stdc++.h>
using namespace std;
#define int long long 
const int N=100100;
int n;
struct Node{
	int l,r;
}tree[N];
void pre_order(int x){
	cout<<x<<" ";
	if(tree[x].l!=0){
		pre_order(tree[x].l);
	}
	if(tree[x].r!=0){
		pre_order(tree[x].r);
	}
}
void in_order(int x){
	if(tree[x].l!=0){
		pre_order(tree[x].l);
	}
	cout<<x<<" ";
	if(tree[x].r!=0){
		pre_order(tree[x].r);
	}
}
void post_order(int x){
	if(tree[x].l!=0){
		pre_order(tree[x].l);
	}
	if(tree[x].r!=0){
		pre_order(tree[x].r);
	}
	cout<<x<<" ";	
}
signed main(){
	ios::sync_with_stdio(0);
	cin.tie(0);cout.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++){
		cin>>tree[i].l>>tree[i].r;
	}
	pre_order(1);
	cout<<"\n";
	in_order(1);
	cout<<"\n";
	post_order(1);
	
}