#include <bits/stdc++.h>

using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");

const int NMAX = 100005;
vector<int> g[NMAX];
int maxim, maxnode;

queue<pair<int, int> > q;
bool visited[NMAX];
void bfs(int u) {
    memset(visited, 0, sizeof visited);
    q.push({u, 1});
    visited[u] = 1;
    while(q.size()) {
        auto s = q.front();
        q.pop();
        if(s.second > maxim) {
            maxim = s.second;
            maxnode = s.first;
        }
        for(auto it : g[s.first]) {
            if(!visited[it]) {
                visited[it] = 1;
                q.push({it, s.second + 1});
            }
        }

    }
}

int main() {
    //freopen("A.in", "r", stdin);
    //freopen("a.out", "w", stdout);
    ios::sync_with_stdio(false);
    int n;
    in >> n;
    for(int i = 1; i < n; i ++) {
        int x, y;
        in >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    bfs(1);
    bfs(maxnode);
    out << maxim;
    return 0;
}