#include <bits/stdc++.h>

using namespace std;

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

/**

Arbori

Def: Arborele este un graf conex si fara cicluri
Un arbore cu n noduri are exact n - 1 muchii

*/


vector <int> h[100005];
int n;
int d[100005], viz[100005];


void DFS (int x)
{
    viz[x] = 1;
    for (int i : h[x])
        if (viz[i] == 0)
        {
            d[i] = d[x] + 1;
            DFS(i);
        }
}

int main()
{
    int maxim = 0, nod_max;
    fin >> n;
    for (int i = 1; i <= n - 1; i++)
    {
        int x , y;
        fin >> x >> y;
        h[x].push_back(y);
        h[y].push_back(x);
    }
    DFS(1);
    for (int i = 1; i <= n; i++)
    {
        if (d[i] > maxim)
        {
            maxim = d[i];
            nod_max = i;
        }
        d[i] = 0;
        viz[i] = 0;
    }
    DFS(nod_max);
    maxim = 0;
    for (int i = 1; i <= n; i++)
        maxim = max (maxim , d[i]);
    fout << maxim + 1 << "\n";
    return 0;
}