#include <fstream>

using namespace std;

ifstream fin ("darb.in");
ofstream fout ("darb.out");

struct nod
{
    int vf;
    struct nod* urm;
};

typedef nod*  LSI;
LSI L[100002], p;

int n, m, i, poz, maxim=0;
bool uz[100002];

void citire();
void inserare(LSI& L, int);
void dfs(int nod, int d);

int main()
{
    citire();
    dfs(1,1);
    for(i=0; i<=n; i++)
        uz[i]=0;
    dfs(poz, 1);
    fout<<maxim;
    return 0;
}

void citire()
{
    int x, y, i;
    fin>>n;
    while (fin>>x>>y)
        {
         inserare(L[x], y);
         inserare(L[y], x);
        }
}

void inserare(LSI& L, int x)
{
    nod* q = new nod;
    q->vf=x;
    if(L==NULL)
        L=q;
    else
    {
        q->urm=L->urm;
        L->urm=q;
    }
}

void dfs(int x, int d)
{
    int i;
    LSI p=new nod;
    uz[x]=1;
    if(d>maxim)
    {
        maxim=d;
        poz=x;
    }
    for(p=L[x]; p; p=p->urm)
    {
        if(uz[p->vf]==0)
            dfs(p->vf, d+1);
    }
}