#include <fstream>
#include <vector>
#define VAL 100005

using namespace std;

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

int N, i, j, a, b;
int mx, rad, best;
int dist1[VAL];
int dist2[VAL];
bool viz1[VAL];
bool viz2[VAL];
vector<int> G[VAL];

void dfs1(int nod)
{
    vector<int> :: iterator it;
    viz1[nod]=true;
    for (it=G[nod].begin(); it!=G[nod].end(); it++)
    {
        if (viz1[*it]==false)
        {
            dist1[*it]=dist1[nod]+1;
            if (mx<dist1[*it])
            {
                mx=dist1[*it];
                rad=*it;
            }
            dfs1(*it);
        }
    }
}

void dfs2(int nod)
{
    vector<int> :: iterator it;
    viz2[nod]=true;
    for (it=G[nod].begin(); it!=G[nod].end(); it++)
    {
        if (viz2[*it]==false)
        {
            dist2[*it]=dist2[nod]+1;
            best=max(best, dist2[*it]);
            dfs2(*it);
        }
    }
}

int main()
{
    fin >> N;
    for (i=1; i<N; i++)
    {
        fin >> a >> b;
        G[a].push_back(b);
        G[b].push_back(a);
    }
    dfs1(1);
    dfs2(rad);
    fout << best+1 << '\n';
    fin.close();
    fout.close();
    return 0;
}