#include <bits/stdc++.h>
#pragma GCC optimize("O3")
using namespace std;
const int MAX = 5e5 + 5;
const long long MAX2 = 11;
const long long MOD = 1000000007;
const long long MOD2 = 1000000006;
const long long INF = 2e18;
const int dr[] = {1, 0, -1, 0, 1, 1, -1, -1, 0};
const int dc[] = {0, 1, 0, -1, 1, -1, 1, -1, 0};
const double pi = acos(-1);
const double EPS = 1e-9;
const int block = 2000;
int n, id, a, b;
vector<int> v[MAX], ans[MAX];
void dfs(int nw, int par) {
  for (auto i : v[nw]) {
    if (i == par) continue;
    ans[i].push_back(++id);
  }
  ans[nw].push_back(++id);
  reverse(v[nw].begin(), v[nw].end());
  for (auto i : v[nw]) {
    if (i == par) continue;
    dfs(i, nw);
  }
  return;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 2; i <= n; ++i)
    cin >> a >> b, v[a].push_back(b), v[b].push_back(a);
  ans[1].push_back(++id);
  dfs(1, 0);
  for (int i = 1; i <= n; ++i) cout << ans[i][0] << ' ' << ans[i][1] << '\n';
  return 0;
}
