#include <bits/stdc++.h>
using namespace std;
const long long nax = 5e5 + 5;
vector<long long> graph[nax];
long long t = 1;
bool vis[nax];
long long x[nax], y[nax];
void dfs(long long cur, long long p) {
  for (long long i = graph[cur].size() - 1; i >= 0; i--) {
    long long node = graph[cur][i];
    if (node != p) {
      x[node] = t++;
    }
  }
  y[cur] = t++;
  for (long long u : graph[cur]) {
    if (u != p) dfs(u, cur);
  }
}
signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  ;
  long long n;
  cin >> n;
  if (n == 1) {
    cout << "1 2" << endl;
    return 0;
  }
  for (long long i = 1; i <= n - 1; i++) {
    long long a, b;
    cin >> a >> b;
    graph[a].push_back(b);
    graph[b].push_back(a);
  }
  for (long long i = 1; i <= n; i++) {
    sort(graph[i].begin(), graph[i].end());
  }
  x[1] = t++;
  dfs(1, -1);
  for (long long i = 1; i <= n; i++) {
    cout << x[i] << " " << y[i] << endl;
  }
  return 0;
}
