#include <bits/stdc++.h>
#pragma GCC diagnostic ignored "-Wunused-result"
#pragma GCC diagnostic ignored "-Wunused-function"
using namespace std;
namespace {
namespace unolight {
template <class T>
void _R(T &x) {
  cin >> x;
}
void _R(int &x) { scanf("%d", &x); }
void _R(int64_t &x) { scanf("%" PRId64, &x); }
void _R(double &x) { scanf("%lf", &x); }
void _R(char &x) { scanf(" %c", &x); }
void _R(char *x) { scanf("%s", x); }
void R() {}
template <class T, class... U>
void R(T &head, U &...tail) {
  _R(head);
  R(tail...);
}
template <class T>
void _W(const T &x) {
  cout << x;
}
void _W(const int &x) { printf("%d", x); }
void _W(const int64_t &x) { printf("%" PRId64, x); }
void _W(const double &x) { printf("%.16f\n", x); }
void _W(const char &x) { putchar(x); }
void _W(const char *x) { printf("%s", x); }
template <class T>
void _W(const vector<T> &x) {
  for (auto i = x.begin(); i != x.end(); _W(*i++))
    if (i != x.cbegin()) putchar(' ');
}
void W() {}
template <class T, class... U>
void W(const T &head, const U &...tail) {
  _W(head);
  putchar(sizeof...(tail) ? ' ' : '\n');
  W(tail...);
}
template <class T>
inline bool chmax(T &a, const T &b) {
  return b > a ? a = b, true : false;
}
template <class T>
inline bool chmin(T &a, const T &b) {
  return b < a ? a = b, true : false;
}
template <class T>
using MaxHeap = priority_queue<T>;
template <class T>
using MinHeap = priority_queue<T, vector<T>, greater<T>>;
template <class T, class F = less<T>>
void sort_uniq(vector<T> &v, F f = F()) {
  sort(begin(v), end(v), f);
  v.resize(unique(begin(v), end(v)) - begin(v));
}
const int N = 5e5 + 5;
int n, ans1[N], ans2[N];
vector<int> e[N];
int k = 0;
void go(int u, int fa) {
  vector<int> child;
  for (int v : e[u]) {
    if (v ^ fa) child.push_back(v);
  }
  for (int v : child) {
    ans1[v] = ++k;
  }
  ans2[u] = ++k;
  reverse(begin(child), end(child));
  for (int v : child) {
    go(v, u);
  }
}
void main() {
  R(n);
  for (int i = 0; i < int(n - 1); i++) {
    int a, b;
    R(a, b);
    e[a].push_back(b);
    e[b].push_back(a);
  }
  ans1[1] = ++k;
  go(1, 0);
  for (int i = (1); i <= int(n); i++) {
    W(ans1[i], ans2[i]);
  }
}
}  // namespace unolight
}  // namespace
int main() {
  unolight::main();
  return 0;
}
