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

using namespace std;

int n, x, y, frunza, nivMax;
bool viz[nmax];
vector <int> G[nmax];

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

int main() {
    
    ifstream fin("darb.in");
    ofstream fout("darb.out");
    
    fin >> n;
    for (int i = 1; i <= n; i++) {
        fin >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }
    
    dfs(1, 1);
    memset(viz, false, sizeof(viz));
    dfs(frunza, 1);
    
    fout << nivMax << "\n";
    
    fin.close();
    fout.close();
    
    return 0;
}