#include <iostream>
#include <fstream>
#include <vector>
#include <queue>

using namespace std;

#define MAX 100005

vector < int > v[MAX];
queue < int > coada;
unsigned n, viz[100005], x, y, rez, last, first, diametru[100005];

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

int dfs(int nod)
{
    viz[nod] = 1;
    for(int i = 0; i < v[nod].size(); i++)
    {
        if(viz[v[nod][i]] == 0)
            return dfs(v[nod][i]);
    }
    return nod;
}

void diam(int x)
{
    coada.push(x);
    viz[x] = 1;
    while(!coada.empty())
    {
        int nod = coada.front();
        coada.pop();
        for(int i = 0; i < v[nod].size(); i++)
        {
            if(viz[v[nod][i]] == 0)
            {
                coada.push(v[nod][i]);
                viz[v[nod][i]] = 1;
                diametru[v[nod][i]] = diametru[nod] + 1;
            }
        }
    }
}

int main()
{
    fin >> n;
    for(int i = 1; i < n; i++)
    {
        fin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }

    last = dfs(1);
    for(int i = 1; i <= n; i++)
        viz[i] = 0;
    first = dfs(last);
    for(int i = 1; i <= n; i++)
        viz[i] = 0;
    diam(last);
    for(int i = 1; i <= n; i++)
        rez = max(rez, diametru[i]);
    fout << rez + 1 << "\n";
    return 0;
}