#include <fstream>
#include <vector>

#define NMAX 100005

using namespace std;

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

int n, dist[NMAX], nodmax;
vector <int> G[NMAX];

void DFS(int nod)
{
    for(auto i : G[nod])
        if(!dist[i])
        {
            dist[i] = dist[nod] + 1;
            if(dist[i] > dist[nodmax]) nodmax = i;
            DFS(i);
        }
}

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

    dist[1] = 1;
    DFS(1);
    for(int i = 1; i <= n; ++i) dist[i] = 0;
    dist[nodmax] = 1;
    DFS(nodmax);
    fout << dist[nodmax];
    fout.close();
    return 0;
}