#include <bits/stdc++.h>
using namespace std;
const int MAX_N = 500005;
vector<int> G[MAX_N];
int n, k = 1, L[MAX_N], P[MAX_N];
bool odw[MAX_N];
int A[2 * MAX_N];
void dfs(int v) {
  odw[v] = true;
  int d = G[v].size();
  for (int i = d - 1; i >= 0; i--) {
    int u = G[v][i];
    if (odw[u]) continue;
    k++;
    A[k] = u;
  }
  k++;
  A[k] = v;
  for (int i = 0; i < d; i++) {
    int u = G[v][i];
    if (odw[u]) continue;
    dfs(u);
  }
}
int main() {
  ios_base::sync_with_stdio(0);
  cin >> n;
  for (int i = 1; i < n; i++) {
    int a, b;
    cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  A[1] = 1;
  dfs(1);
  for (int i = 1; i <= 2 * n; i++) {
    int x = A[i];
    if (L[x] == 0)
      L[x] = i;
    else
      P[x] = i;
  }
  for (int i = 1; i <= n; i++) cout << L[i] << " " << P[i] << endl;
  return 0;
}
