#include <iostream>
#include <vector>

using namespace std;
vector<vector<int>> g;
vector<bool> used;

pair<int, int> dfs(int v) {
    used[v] = true;
    pair<int, int> best = {v, 0};
    for (const auto& u : g[v]) {
        if (!used[u]) {
            auto res = dfs(u);
            if (res.second > best.second) best = res;
        }
    }
    ++best.second;
    return best;
}

int main() {
    int n;
    cin >> n;
    g.assign(n, vector<int>());
    used.assign(n, false);
    for (int i = 0; i < n - 1; ++i) {
        int a, b;
        cin >> a >> b;
        --a, --b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    auto res1 = dfs(0);
    used.assign(n, false);
    auto res2 = dfs(res1.first);
    cout << res2.second - 1<< "\n";
    return 0;
}