#include <bits/stdc++.h>
using namespace std;
template <typename T>
inline bool uax(T &x, T y) {
  return (y > x) ? x = y, true : false;
}
template <typename T>
inline bool uin(T &x, T y) {
  return (y < x) ? x = y, true : false;
}
string to_string(char c) { return "'" + string(1, c) + "'"; }
string to_string(string s) { return '"' + s + '"'; }
string to_string(const char *s) { return to_string((string)s); }
template <typename A>
string to_string(A);
template <typename A, typename B>
string to_string(pair<A, B> p) {
  return "(" + to_string(p.first) + ": " + to_string(p.second) + ")";
}
template <typename A>
string to_string(A v) {
  bool f = false;
  string r = "{";
  for (auto x : v) {
    if (f) r += ", ";
    r += to_string(x);
    f = true;
  }
  return r += "}";
}
template <typename A>
string to_string(vector<vector<A>> v) {
  string r;
  for (auto x : v) r += "\n" + to_string(x);
  return r;
}
int Nerr;
template <typename A>
string to_string(A *p) {
  return to_string(vector<A>(p, p + Nerr));
}
void err(istream_iterator<string>) { cerr << endl; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " =: " << to_string(a) << "; ";
  err(++it, args...);
}
template <typename T>
void kek(T ans) {
  cout << ans << endl;
  exit(0);
}
int const MOD = 1e9 + 7;
long long const INF = 1e18 + 42;
const int N = 1e5 + 42;
vector<int> g[N];
int cov[N];
int nei[N];
int cnt[N];
multiset<int> cs[N];
multiset<int> ns[N];
int ans;
void pre(int u = 0, int p = -1) {
  cnt[u] = -1;
  cs[u] = {0};
  ns[u] = {1};
  for (int v : g[u])
    if (v ^ p) {
      pre(v, u);
      cs[u].insert(nei[v] + cnt[v]);
      ns[u].insert(max(1 + cov[v], nei[v] + cnt[v]));
      cnt[u]++;
    }
  cov[u] = *cs[u].rbegin();
  nei[u] = *ns[u].rbegin();
}
void dfs(int u = 0, int p = -1) {
  cov[u] = *cs[u].rbegin();
  nei[u] = *ns[u].rbegin();
  uax(ans, 1 + cov[u]);
  --cnt[u];
  for (int v : g[u])
    if (v != p) {
      cs[u].erase(cs[u].find(nei[v] + cnt[v]));
      ns[u].erase(ns[u].find(max(nei[v] + cnt[v], 1 + cov[v])));
      cov[u] = *cs[u].rbegin();
      nei[u] = *ns[u].rbegin();
      cs[v].insert(nei[u] + cnt[u]);
      ns[v].insert(max(nei[u] + cnt[u], 1 + cov[u]));
      ++cnt[v];
      dfs(v, u);
      --cnt[v];
      cs[v].erase(cs[v].find(nei[u] + cnt[u]));
      ns[v].erase(ns[v].find(max(nei[u] + cnt[u], 1 + cov[u])));
      cov[v] = *cs[v].rbegin();
      nei[v] = *ns[v].rbegin();
      cs[u].insert(nei[v] + cnt[v]);
      ns[u].insert(max(nei[v] + cnt[v], 1 + cov[v]));
    }
  ++cnt[u];
}
int32_t main() {
  cin.tie(nullptr)->sync_with_stdio(false);
  int n;
  cin >> n;
  for (int i = 0; i < n - 1; ++i) {
    int u, v;
    cin >> u >> v, --u, --v;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  pre(), dfs(), kek(ans);
}
