#include <fstream>
#include <vector>
#define len 100010
#define pb push_back

using namespace std;

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

vector<unsigned> v[len];

unsigned N, last, cmax, lung[len];
bool viz[len];

void dfs(unsigned nod)
{
    viz[nod] = true;
    for(unsigned k = 0; k < v[nod].size(); ++k)
        if(!viz[v[nod][k]])
        {
            lung[v[nod][k]] = lung[nod] + 1;
            if(lung[v[nod][k]] > cmax)
            {
                cmax = lung[v[nod][k]];
                last = v[nod][k];
            }
            dfs(v[nod][k]);
        }
}

int main()
{
    in >> N;
    for(unsigned i = 1; i < N; ++i)
    {
        unsigned x, y;
        in >> x >> y;
        v[x].pb(y);
        v[y].pb(x);
    }
    lung[1] = 1;
    dfs(1);
    for(unsigned i = 1; i <= N; ++i)
    {
        viz[i] = false;
        lung[i] = (i == last ? 1 : 0);
    }
    cmax = 0;
    dfs(last);
    out << cmax;
    return 0;
}