#include <bits/stdc++.h>

using namespace std;

const int NMAX = 1e5;
vector <int> e[NMAX + 5];
queue <int> q;
bool viz[NMAX + 5];
int dist[NMAX + 5];
int node,mx = 0;

void bfs(int nod) {
    q.push(nod);
    dist[nod] = 1;
    viz[nod] = 1;
    while (!q.empty()) {
        nod = q.front();
        q.pop();
        for (int i = 0;i < e[nod].size();i++) {
            if (!viz[e[nod][i]]) {
                viz[e[nod][i]] = 1;
                mx = dist[nod] + 1;
                dist[e[nod][i]] = mx;
                node = e[nod][i];
                q.push(e[nod][i]);
            }
        }
    }
}
int main()
{
    ifstream fin("darb.in");
    ofstream fout("darb.out");
    int n,a,b;
    fin >> n;
    for (int i = 0;i < n - 1;i++) {
        fin >> a >> b;
        e[a].push_back(b);
        e[b].push_back(a);
    }
    bfs(1);
    memset(viz, 0, sizeof(viz));
    memset(dist, 0, sizeof(dist));
    bfs(node);
    fout << mx;
    return 0;
}