#include <bits/stdc++.h>
using namespace std;

#define SZ(a) (int)a.size()
#define ALL(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a); i<(b); ++i)
#define RFOR(i, b, a) for (int i = (b)-1; i>=(a); --i)
#define MP make_pair
#define PB push_back
#define F first
#define S second

typedef long long LL;
typedef pair<int, int> PII;
typedef vector<int> VI;

const int N = 1e4 + 47;
VI g[N];
int c1[N];
int c2[N];
int c = 1;

void dfs(int v, int p, int col)
{
	if (SZ(g[v]) == 1)
	{
		c1[v] = c1[p];
		c2[v] = c2[p];
		return;
	}
	c1[v] = col;
	c2[v] = c++;
	for (auto to : g[v])
		if (to != p)
			dfs(to, v, c2[v]);
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);
	
	int n;
	cin >> n;
	if (n == 2)
	{
		cout << "47 74\n47 74\n";
		return 0;
	}
	FOR(i, 0, n - 1)
	{
		int a, b;
		cin >> a >> b;
		a--, b--;
		g[a].PB(b);
		g[b].PB(a);
	}
	
	int root = -1;
	FOR(i, 0, n)
	{
		if(SZ(g[i]) > 1)
			root = i;
	}
	c1[root] = c++;
	c2[root] = c++;
	dfs(g[root][0], root, c1[root]);
	FOR(i, 1, SZ(g[root]))
		dfs(g[root][i], root, c2[root]);	
	FOR(i, 0, n)
	{
		cout << c1[i] << ' ' << c2[i] << '\n';
	}
	
	return 0;
}