Seminar2

#include <iostream>
#include <vector>

struct Node {
  int Parent = 0;
  std::vector<int> Children;
  int Height = 0;
};

void DFS(int v, std::vector<Node>& tree) {
  for (int u : tree[v].Children) {
    DFS(u, tree);
    tree[v].Height = std::max(tree[v].Height, tree[u].Height + 1);
  }
}

int Diametr(std::vector<Node>& tree) {
  int result = 0;
  for (int i = 0; i < tree.size(); ++i) {
    if (tree[i].Children.empty()) continue;
    if (tree[i].Children.size() == 1) {
      result = std::max(result, tree[i].Height);
    } else {
      std::pair<int, int> best = {tree[tree[i].Children[0]].Height, tree[tree[i].Children[1]].Height};
      if (best.first > best.second) std::swap(best.first, best.second);
      for (int j = 2; j < tree[i].Children.size(); ++j) {
        if (tree[tree[i].Children[j]].Height >= best.second) {
          best.first = best.second;
          best.second = tree[tree[i].Children[j]].Height;
        } else if (tree[tree[i].Children[j]].Height >= best.first) {
          best.first = tree[tree[i].Children[j]].Height;
        }
      }
      result = std::max(result, best.first + best.second + 2);
    }
  }
  return result;
}

int main() {
  int n = 0; std::cin >> n;
  std::vector<Node> tree(n);
  for (int i = 0; i < n - 1; ++i) {
    int a, b; std::cin >> a >> b;
    if (a > b) std::swap(a, b);
    tree[b].Parent = a;
    tree[a].Children.push_back(b);
  }

  DFS(0, tree);

  for (int i = 0; i < n; ++i) {
    std::cout << i << ": [Height=" << tree[i].Height << "], [Children=";
    for (int& x : tree[i].Children) std::cout << x << ",";
    std::cout << "]\n";
  }

  std::cout << Diametr(tree);

  return 0;
}