#include <bits/stdc++.h>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
const int NMAX = 1e5 + 1, INF = 1e9;
int n, dist1[NMAX], dist2[NMAX];
vector<int> adj[NMAX];

void bfs(int source, int dist[])
{
    fill(dist + 1, dist + n + 1, INF);
    dist[source] = 0;
    queue<int> Q({source});
    while(!Q.empty())
    {
        int node = Q.front(); Q.pop();
        for(int next : adj[node])
        {
            if(dist[next] == INF)
            {
                dist[next] = dist[node] + 1;
                Q.push(next);
            }
        }
    }
}

int main()
{
    fin >> n;
    for(int i = 1; i <= n - 1; i++)
    {
        int u, v;
        fin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    bfs(1, dist1);
    int farthest = 1;
    for(int i = 1; i <= n; i++)
        farthest = (dist1[i] > dist1[farthest] ? i : farthest);
    bfs(farthest, dist2);
    fout << *max_element(dist2 + 1, dist2 + n + 1) + 1;

    fin.close();
    fout.close();
    return 0;
}