#include <iostream>
#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream in("darb.in");
ofstream out("darb.out");
const int maxn = 100005;
vector <int> v[maxn];
int dist[maxn];
int n;

void bfs(int nod)
{
    for(int i = 1; i <= n; i++)
        dist[i] = (1 << 30);
    dist[nod] = 0;
    queue <int> q;
    q.push(nod);
    while(!q.empty())
    {
        int nod = q.front();
        q.pop();
        for(auto it : v[nod])
        {
            if(dist[it] > dist[nod] + 1)
            {
                dist[it] = dist[nod] + 1;
                q.push(it);
            }
        }
    }
}

int main()
{
    in >> n;
    for(int i = 1; i < n; i++)
    {
        int x, y;
        in >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    bfs(1);
    int nod = 0;
    int mx = 0;
    for(int i = 1; i <= n; i++)
    {
        if(dist[i] > mx)
        {
            nod = i;
            mx = dist[nod];
        }
    }
    bfs(nod);
    mx = 0;
    for(int i = 1; i <= n; i++)
        mx = max(mx, dist[i]);
    out << mx + 1 << "\n";
    return 0;
}