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

ifstream f("darb.in");
ofstream g("darb.out");

#defin MAXSIZE 10010
vector<int> graf[MAXSIZE];
int dist[MAXSIZE];

void bfs(int node)
{
    dist[node] = 1;
    queue<int> q;
    q.push(node);
    while(!q.empty())
    {
        node = q.front();
        q.pop();
        for(int i = 0; i < (int)graf[node].size(); i++)
        {
            int next = graf[node][i];
            if(!dist[next])
            {
                dist[next] = dist[node] + 1;
                q.push(next);
            }
        }
    }
}

int main()
{
    int n;
    f >> n;
    for(int i = 1; i <= n - 1; i++)
    {
        int x, y;
        f >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    bfs(1);
    int maximum = 0;
    int node = 1;
    for(int i = 1; i <= n; i++)
    {
        if(dist[i] > maximum)
        {
            maximum = dist[i];
            node = i;
        }
    }
    for(int i = 1; i <= n; i++)
    {
        dist[i] = 0;
    }
    bfs(node);
    maximum = 0;
    for(int i = 1; i <= n; i++)
    {
        maximum = max(maximum, dist[i]);
    }
    g << maximum;
    return 0;
}