#include <bits/stdc++.h>
#define L 100005
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");

vector <int> G[L];
int lev1[L], lev2[L];
bool vis1[L], vis2[L];

void DFS1(int node){
  vis1[node] = true;
  for (auto it : G[node])
    if (!vis1[it]){
      lev1[it] = lev1[node] + 1;
      DFS1(it);
    }
}

void DFS2(int node){
  vis2[node] = true;
  for (auto it : G[node])
    if (!vis2[it]){
      lev2[it] = lev2[node] + 1;
      DFS2(it);
    }
}

int main(){
  int n;
  fin >> n;
  for (int i = 1; i < n; i++){
    int a, b;
    fin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  lev1[1] = 1;
  DFS1(1);
  int node = 0, mxlev = 0;
  for (int i = 1; i <= n; i++)
    if (lev1[i] > mxlev){
      node = i;
      mxlev = lev1[i];
    }
  lev2[node] = 1;
  DFS2(node);
  mxlev = 0;
  for (int i = 1; i <= n; i++)
    mxlev = max(mxlev, lev2[i]);
  fout << mxlev << "\n";
  return 0;
}