#include <fstream>
#include <vector>
#include <queue>
using namespace std;
ifstream fin("darb.in");
ofstream fout("darb.out");
const int MAX=100001;
vector <int> muchii[MAX];
int d1[MAX],d2[MAX];
queue <int> q;
int n,f,maxim,rez;
void read()
{
    fin >> n;
    for (int i=1;i<n;i++)
    {
        int x,y;
        fin >> x >> y;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }
}
void bfs1()
{
    q.push(1);
    d1[1]=0;
    for (int i=1;i<=n;i++)
    {
        d1[i]=-1;
    }
    while (!q.empty())
    {
        int nod=q.front();
        q.pop();
        for (unsigned int i=0;i<muchii[nod].size();i++)
        {
            int vecin=muchii[nod][i];
            if (d1[vecin]==-1)
            {
                d1[vecin]=d1[nod]+1;
                if (d1[vecin]>maxim)
                {
                    maxim=d1[vecin];
                    f=vecin;
                }
                q.push(vecin);
            }
        }
    }
}
void bfs2()
{
    for (int i=1;i<=n;i++)
    {
        d2[i]=-1;
    }
    d2[f] = 1;
    q.push(f);
    while (!q.empty())
    {
        int nod=q.front();
        q.pop();
        for (unsigned int i=0;i<muchii[nod].size();i++)
        {
            int vecin=muchii[nod][i];
            if (d2[vecin]==-1)
            {
                d2[vecin]=d2[nod]+1;
                if (d2[vecin]>rez) rez=d2[vecin];
                q.push(vecin);
            }
        }
    }
}
int main()
{
    read();
    bfs1();
    bfs2();
    fout << rez;
    return 0;
}