#include <fstream>
#include <vector>
#include <bitset>

using namespace std;

const int N = 1e5 + 5, oo = 1e9;

vector <int> L[N];
bitset <N> seen;
int d[N], n;

void Read ()
{
    ifstream fin ("darb.in");
    fin >> n;
    for (int i = 1, x, y; i <= n; i++)
    {
        fin >> x >> y;
        L[x].push_back(y);
        L[y].push_back(x);
    }
}

void DFS (int k)
{
    seen[k] = 1;
    for (auto next : L[k])
        if (!seen[next])
        {
            d[next] = 1 + d[k];
            DFS(next);
        }
}

void Solve ()
{
    d[1] = 1;
    DFS(1);
    int i;
    int m = 1;
    for (i = 2; i <= n; i++)
        if (d[m] < d[i]) m = i;
    d[m] = 1;
    seen.reset();
    DFS(m);
    int ans = 0;
    for (int i = 1; i <= n; i++)
        ans = max(ans, d[i]);
    ofstream fout ("darb.out");
    fout << ans << "\n";
    fout.close();
}

int main()
{
    Read();
    Solve();
    return 0;
}