#include <bits/stdc++.h>

using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
int N,a,b,last;
vector <int> v[100001];
queue <int> q;
int viz[100001];
int dist[100001];
int rez;
void bfs(int nod)
{
    q.push(nod);
    viz[nod]=1;
    while(!q.empty())
    {
        for(auto i:v[q.front()])
        {
            if(viz[i]==0)
            {
                viz[i]=1;
                q.push(i);
            }
        }
        if(q.size()==1)
            last=q.front();
         q.pop();
    }
}
int main()
{
    fin>>N;
    for(int i=1;i<=N-1;i++)
    {
        fin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);

    }
    bfs(1);

    for(int i=1;i<=100001;i++)
        viz[i]=0;
    q.push(last);
    while(!q.empty())
    {
        for(auto i:v[q.front()])
        {   if(viz[i]==0)
        {
            q.push(i);
            viz[i]=1;
        }

            dist[i]=max(dist[i],dist[q.front()]+1);
            rez=max(rez,dist[i]);
        }
        q.pop();
    }
    fout<<rez;

    return 0;
}