#include<bits/stdc++.h>
using namespace std;
vector<int> G[30007];
bool w[30007];
int odl[30007], Maks, Knust;
void DFS(int a, int d){
  w[a] = 1;
  odl[a] = d;
  for(int i = 0;i < G[a].size();i++)
    if(!w[G[a][i]])
      DFS(G[a][i], d + 1);
  if(odl[a] > Maks){
    Maks = odl[a];
    Knust = a;
  }
}
int main(){
  int n;
  cin >> n;
  for(int i = 1, a, b;i < n;i++){
    cin >> a >> b;
    G[a].push_back(b);
    G[b].push_back(a);
  }
  DFS(1, 0);
  for(int i = 1;i <= n;i++)
    w[i] = 0;
  DFS(Knust, 0);
  cout << Maks;
}