#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

ifstream cin("darb.in");
ofstream cout("darb.out");

vector<vector<int>> tree;
int n, max_level = -1, max_level_node = 0;
bitset<(int)(1e5 + 5)> viz;

void dfs(int node, int level) {
    viz[node] = 1;
    if (level > max_level) {
        max_level = level;
        max_level_node = node;
    }
    for (int nei : tree[node]) {
        if (!viz[nei]) {
            dfs(nei, level + 1);
        }
    }
}

int main() {
    cin >> n;
    tree.assign(n + 2, vector<int>());
    for (int i = 1 ; i <= n - 1 ; ++i) {
        int src, dest; cin >> src >> dest;
        tree[src].push_back(dest);
        tree[dest].push_back(src);
    }
    dfs(1, 1);
    int s = max_level_node;
    max_level_node = 0;
    max_level = -1;
    viz.reset();
    dfs(s, 1);
    cout << max_level;
    return 0;
}