#include <bits/stdc++.h>
using namespace std;
ifstream fin ("darb.in");
ofstream fout ("darb.out");

int n, x, y, radacina;
vector <int> V[100005];
int departe, lungime;

void fast ()
{
    ios_base::sync_with_stdio(false);
    cin.tie();
}

void dfs (int x, int tata, int nivel)
{
    if (nivel>lungime)
    {
        lungime=nivel;
        departe=x;
    }

    for (int i=0; i<(int)V[x].size(); i++)
    {
        int next = V[x][i];
        if (next!=tata)
            dfs (next, x, nivel+1);

    }
}

int main()
{
    fast();

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


    radacina=1;
    dfs(radacina,0,1);
    lungime=0;
    dfs(departe,0,1);

    fout << lungime;
    return 0;
}