#include <bits/stdc++.h>
using namespace std;
ifstream fin ("darb.in");
ofstream fout ("darb.out");
const int Nmax = 100005;
int dist[Nmax] , n;
vector < int > L[Nmax];
bitset < Nmax > viz;
queue < int > Q;
inline void BFS(int nod)
{
    viz . reset();
    for(int i = 1 ; i <= n ; i++)
        dist[i] = 0;
    Q . push(nod);
    viz[nod] = true;
    dist[nod] = 1;
    while(! Q . empty())
    {
        int x = Q . front();
        Q . pop();
        for(auto i : L[x])
            if(!viz[i])
        {
            viz[i] = true;
            dist[i] = dist[x] + 1;
            Q . push(i);
        }
    }
}
int main()
{
    int left , distmax , x , y;
    fin >> n;
    for(int i = 1 ; i < n ; i++)
        {
            fin >> x >> y;
            L[x] . push_back(y);
            L[y] . push_back(x);
        }
    BFS(1);
    left = 1;
    for(int i = 2 ; i <= n ; i++)
        if(dist[left] < dist[i]) /// capatul stanga al lantului maximal
                left = i;
    BFS(left);
    distmax = 0;
    for(int i = 1 ; i <= n ; i++)
        distmax = max(distmax , dist[i]);
    fout << distmax << "\n";
    fin.close();
    fout.close();
    return 0;
}