#include <bits/stdc++.h>
using namespace std;
const int N = 5e5 + 100;
vector<int> g[N], pp(N, -1), a;
void dfs(int v, int p = -1) {
  a.push_back(v);
  for (int to : g[v]) {
    if (to != p) {
      pp[to] = v;
      dfs(to, v);
    }
  }
}
int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);
  int n;
  cin >> n;
  for (int i = 1; i < n; i++) {
    int x, y;
    cin >> x >> y;
    g[--x].push_back(--y);
    g[y].push_back(x);
  }
  dfs(0);
  reverse((a).begin(), (a).end());
  vector<int> b;
  for (int i : a) {
    b.push_back(i);
    for (int to : g[i]) {
      if (to != pp[i]) {
        b.push_back(to);
      }
    }
  }
  vector<pair<int, int>> ans(n, {-1, -1});
  for (int i = 0; i < (int)(b).size(); i++) {
    if (ans[b[i]].first == -1) {
      ans[b[i]].first = i + 1;
    } else {
      ans[b[i]].second = i + 1;
    }
  }
  ans[0].second = 2 * n;
  for (int i = 0; i < n; i++) {
    cout << ans[i].first << ' ' << ans[i].second << '\n';
  }
  return 0;
}
