#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <iostream>
using namespace std;

const int MAX_N = 10002;

struct node{
	int a, b;
	node(){}
	node(int a_, int b_){
		a = a_; b = b_;
	}
};

int N;
vector<int> G[MAX_N];
node color[MAX_N];
int in[MAX_N];
int V[MAX_N];
int Q[MAX_N], h, t;

int main(){
//	freopen("input.txt","r",stdin);
	
	scanf("%d\n", &N);
	
	if(N == 2){
		printf("1 2\n1 2\n");
		exit(0);
	}

	for(int i = 1 ; i < N ; i ++){
		int u,v; scanf("%d %d\n", &u, &v);
		G[u].push_back(v); in[v] ++;
		G[v].push_back(u); in[u] ++;
	}

	int root = -1;
	for(int i = 1 ; i <= N ; i ++){
		if(in[i] >= 2){
			root = i; break;
		}
	}
	
	h = t = 0;
	Q[h++] = root;
	V[root] = 1;
	color[root] = node(1,2);
	int p = 3;
	while(h > t){
		int c = Q[t++];
		int flag = 0;
		for(int i = 0 ; i < G[c].size() ; i ++){
			int q = G[c][i];
			if(V[q] == 0){
				Q[h++] = q; V[q] = 1;
				if(flag%2 == 0) color[q] = node(color[c].b, p++);
				else color[q] = node(color[c].a, p++);
				flag ++;
			}
		}
	}

	for(int i = 1 ; i <= N ; i ++) 
		printf("%d %d\n", color[i].a, color[i].b);
	return 0;
}