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

#define NMAX 100009

class Task {
 public:
    void solve() {
        read_input();
        print_output(get_result());
    }

 private:
    int n;
    vector<int> nodes[NMAX];
    int parent[NMAX];

    void read_input() {
        ifstream fin("darb.in");
        fin >> n;
        for (int i = 1; i < n; ++i) {
            int x, y;
            fin >> x >> y;
            nodes[x].push_back(y);
            parent[y] = x;
        }
        fin.close();
    }

    int get_result() {
        queue<int> q;
        q.push(1);
        int curr;
        while (!q.empty()) {
            curr = q.front();
            q.pop();
            for (int &neigh : nodes[curr]) {
                q.push(neigh);
            }
        }
        int result = 0;
        vector<int> dist(n + 1, 0);
        dfs(curr, dist, result);
        return result + 1;
    }

    void dfs(int curr, vector<int> &dist, int &result) {
        result = max(result, dist[curr]);
        if (curr != 1 && !dist[parent[curr]]) {
            dist[parent[curr]] = dist[curr] + 1;
            dfs (parent[curr], dist, result);
        }
        for (int &i : nodes[curr]) {
            if (!dist[i]) {
                dist[i] = dist[curr] + 1;
                dfs(i, dist, result);
            }
        }
    }

    void print_output(int result) {
        ofstream fout("darb.out");
        fout << result;
        fout.close();
    }
};

// Please always keep this simple main function!
int main() {
    // Allocate a Task object on heap in order to be able to
    // declare huge static-allocated data structures inside the class.
    Task *task = new Task();
    task->solve();
    delete task;
    return 0;
}