#include <bits/stdc++.h>
using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");

int n;
vector<vector<int>> ad;

void dfs(int node, int father, int depth, pair<int, int>& best) {
    best = max(best, make_pair(depth, node));
    for (int nghb : ad[node])
        if (nghb != father)
            dfs(nghb, node, depth + 1, best);
}

int main() {
    fin >> n;
    ad.resize(n + 1);
    for (int i = 1; i < n; i++) {
        int x, y; fin >> x >> y;
        ad[x].push_back(y);
        ad[y].push_back(x);
    }

    pair<int, int> best;
    dfs(1, 0, 1, best);
    dfs(best.second, 0, 1, best);
    fout << best.first << '\n';

    fout.close();
    return 0;
}