#include <iostream>
#include <fstream>
#include <vector>
#include <bitset>
using namespace std;

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

const int maxn = 1e5 + 5;
vector <int> G[maxn];
bitset <maxn> Vis;
int Dist[maxn], ans, last;

void Dfs(int node, int lev) {
    vector <int> :: iterator it;
    Vis[node] = true;
    for (it = G[node].begin(); it != G[node].end(); it++) {
        if (Vis[*it] == false) {
            Dfs(*it, lev + 1);
        }
    }
    if (lev > ans) {
        ans = lev;
        last = node;
    }
}

int main() {
    ios_base :: sync_with_stdio (false);
    int n, i, x, y;
    fin >> n;
    for (i = 1; i < n; i++) {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    Vis = 0;
    Dfs(1, 1);
    Vis = 0;
    Dfs(last, 1);
    fout << ans << "\n";
    fin.close();
    fout.close();
    return 0;
}