#include <iostream>
#include <fstream>
#include <vector>

#define NMAX 100001

using namespace std;

int max_level = -1;
int max_node;
vector<bool> vis(NMAX, false);
vector<int> adj[NMAX];

void dfs_rec(int node, int level) {
    vis[node] = true;

    if (level > max_level) {
        max_level = level;
        max_node = node;
    }

    for (int i = 0; i < adj[node].size(); ++i) {
        if (!vis[adj[node][i]]) {
            dfs_rec(adj[node][i], level + 1);
        }
    }
}

void dfs(int n) {
    int level = 0;

    for (int i = 1; i <= n; ++i) {
        if (!vis[i]) {
            dfs_rec(i, level);
        }
    }

    vis.assign(n + 1, false);
    level = 0;

    dfs_rec(max_node, level);
}

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

    int n;
    fin >> n;

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

    dfs(n);

    fout << max_level + 1 << "\n";

    return 0;
}