#include <bits/stdc++.h>
using namespace std;
const double PI = 2 * acos(0.0);
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
mt19937_64 rng_64(chrono::steady_clock::now().time_since_epoch().count());
const string DIGITS = "0123456789";
const string ALPH = "abcdefghijklmnopqrstuvwxyz";
template <class T0, class T1>
inline ostream &operator<<(ostream &out, pair<T0, T1> &a) {
  return out << "{" << a.first << ", " << a.second << "}";
}
template <class T0, class T1, class T2>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << "}";
}
template <class T0, class T1, class T2, class T3>
inline ostream &operator<<(ostream &out, tuple<T0, T1, T2, T3> &a) {
  return out << "{" << get<0>(a) << ", " << get<1>(a) << ", " << get<2>(a)
             << ", " << get<3>(a) << "}";
}
template <class T>
inline ostream &operator<<(ostream &out, vector<T> &a) {
  out << "[";
  for (int i = 0; i < int(a.size()); ++i)
    out << a[i] << vector<string>{", ", "]  "}[i + 1 == a.size()];
  return out;
}
void smain();
signed main() {
  ios::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cout << setprecision(12) << fixed;
  smain();
  return 0;
}
const int N = 5e5 + 10;
int n;
vector<int> g[N];
int cur = 1;
int lf[N], rf[N];
void dfs(int v, int par) {
  bool leaf = true;
  int deg = 0;
  for (int to : g[v]) {
    if (to == par) continue;
    leaf = false;
    deg++;
  }
  if (leaf) {
    rf[v] = cur++;
  } else {
    rf[v] = deg + cur;
    int j = 0;
    for (int to : g[v]) {
      if (to == par) continue;
      lf[to] = cur + j++;
    }
    cur += deg + 1;
    reverse(g[v].begin(), g[v].end());
    for (int to : g[v]) {
      if (to == par) continue;
      dfs(to, v);
    }
  }
}
void smain() {
  cin >> n;
  for (int i = 0; i < int(n - 1); ++i) {
    int u, v;
    cin >> u >> v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  lf[1] = 1;
  cur = 2;
  dfs(1, -1);
  for (int i = 1; i <= n; ++i) {
    cout << lf[i] << ' ' << rf[i] << '\n';
  }
}
