#include <iostream>
#include <vector>
#include <fstream>
using namespace std;

ifstream fin("darb.in");
ofstream fout("darb.out");
const int noduriMax = 200000;
vector <int> muchii[noduriMax];
bool used[noduriMax];
int distanta[noduriMax];
int n;
int dist = 0;

void dfs(int nod)
{
    dist++;
    used[nod] = true;
    for (int i = 0; i < muchii[nod].size(); ++i)
    {
        int vecin = muchii[nod][i];
        if (used[vecin] == false)
        {
            distanta[vecin] = dist;
            dfs(vecin);
        }
    }
    dist--;
}

int main()
{
    fin >> n;
    for (int i = 1; i < n; ++i)
    {
        int x, y;
        fin >> x >> y;
        muchii[x].push_back(y);
        muchii[y].push_back(x);
    }
    distanta[1] = 0;
    dfs(1);
    int maxx_nod;
    int maxx_parcurs = -1;
    for (int i = 1; i <= n; ++i)
        if (maxx_parcurs < distanta[i])
        {
            maxx_parcurs = distanta[i];
            maxx_nod = i;
        }
    dist = 0;
    distanta[maxx_nod] = 0;
    for (int i = 1; i <= n; ++i)
        used[i] = false;
    dfs(maxx_nod);
    int maxx = -1;
    for (int i = 1; i <= n; ++i)
        maxx = max(distanta[i], maxx);
    fout << maxx + 1;
}