#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin ("darb.in");
ofstream fout ("darb.out");

int n, m, viz[100005], d[100005], last;
vector <int> L[100005];
queue <int> q;

void citire()
{
    fin >> n;
    m=n-1;
    int x, y;
    while(m--)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void BFS(int nod)
{
    viz[nod]=1;
    d[nod]=0;
    q.push(nod);
    while(!q.empty())
    {
        int v=q.front();
        last=v;
        q.pop();
        for(unsigned int i=0;i<L[v].size();i++)
        {
            int vecin=L[v][i];
            if(viz[vecin]!=1)
            {
                viz[vecin]=1;
                d[vecin]=d[v]+1;
                q.push(vecin);
            }
        }
    }
}

int main()
{
    int p;
    citire();
    BFS(1);
    p=last;
    for(int i=1;i<=n;i++)
        viz[i]=0;
    BFS(p);
    fout << d[last]+1;
    return 0;
}