#include <iostream>
#include <fstream>
#include <vector>
#include <cstring>
#define nmax 100005

using namespace std;

int N;
int nivelMaxim, frunza;
bool viz[nmax];
vector <int> muchie[nmax];

void dfs(int nod, int nivel) {
    viz[nod] = true;
    for (int i = 0; i < muchie[nod].size(); i++)
        if (!viz[muchie[nod][i]])
            dfs(muchie[nod][i], nivel+1);
    if (nivel > nivelMaxim) {
        nivelMaxim = nivel;
        frunza = nod;
    }
}

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

    fin >> N;
    
    int x, y;
    
    for (int i  = 1; i < N; i++) {
        fin >> x >> y;
        muchie[x].push_back(y);
        muchie[y].push_back(x);
    }
    
    dfs(1, 1);
    memset(viz, false, sizeof(viz)), nivelMaxim = 0;
    dfs(frunza, 1);
    fout << nivelMaxim << "\n";
    
    fin.close();
    fout.close();
    
    return 0;
}