#include <bits/stdc++.h>
using namespace std;
const int N = 6e5 + 6;
const long long MOD = 1e9 + 7;
pair<int, int> pat[N];
vector<int> g[N];
int dfs(int v, int ind, int par = -1) {
  int qan = g[v].size() - 1;
  if (par == -1) qan++;
  pat[v].second = ind + qan;
  int tv = pat[v].second;
  for (auto to : g[v]) {
    if (to == par) continue;
    pat[to].first = ind++;
  }
  reverse(g[v].begin(), g[v].end());
  for (auto to : g[v]) {
    if (to == par) continue;
    tv = dfs(to, tv + 1, v);
  }
  return tv;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  ;
  cout.precision(13);
  cout.setf(ios::showpoint);
  int n;
  cin >> n;
  for (int i = 0; i < (n - 1); ++i) {
    int goa, gob;
    cin >> goa >> gob;
    g[goa].push_back(gob);
    g[gob].push_back(goa);
  }
  pat[1].first = 0;
  dfs(1, 1);
  for (int i = (1); i <= (n); ++i) {
    cout << pat[i].first + 1 << " " << pat[i].second + 1 << endl;
  }
  return 0;
}
