#include <bits/stdc++.h>

using namespace std;

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

void usain_bolt()
{
    ios::sync_with_stdio(false);
    fin.tie(0);
}

const int N = 1e5 + 5;

vector < int > a[N];
vector < int > d(N, 2e9);

void bfs(int k)
{
    vector < bool > in(N, false);
    queue < int > q;
    d[k] = 0;
    q.push(k);
    while(!q.empty()) {
        int k = q.front();
        q.pop();
        in[k] = false;
        for(auto v : a[k]) {
            if(d[v] > d[k] + 1) {
                d[v] = d[k] + 1;
                if(in[v] == false) {
                    q.push(v);
                    in[v] = true;
                }
            }
        }
    }
}

int main()
{
    usain_bolt();

    int n;

    fin >> n;
    for(int i = 1; i < n; ++i) {
        int x, y;

        fin >> x >> y;
        a[x].push_back(y);
        a[y].push_back(x);
    }
    bfs(1);
    int mx = 0, chosen = 1;
    for(int i = 1; i <= n; ++i) {
        if(d[i] > mx) {
            chosen = i;
        }
        mx = max(mx, d[i]);
    }
    d.assign(N, 2e9);
    bfs(chosen);
    mx = 0;
    for(int i = 1; i <= n; ++i) {
        mx = max(mx, d[i]);
    }
    fout << mx + 1;
    return 0;
}