#include <bits/stdc++.h>
using namespace std;

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

const int NMax = 100001;
int N, diam, ult;
bool viz[NMax];
vector <int> lista[NMax];

void citire() {
    int x, y;
    f >> N;
    for (int i = 1; i < N; i++) {
        f >> x >> y;
        lista[x].push_back(y);
        lista[y].push_back(x);
    }
}

void DFS(int x, int niv) {
    if (niv > diam) {
        diam = niv;
        ult = x;
    }
    viz[x] = 1;
    for (auto &it : lista[x]) {
        if (viz[it] == 0)
            DFS(it,niv+1);
    }
}

int main()
{
    citire();
    DFS(1,1);
    for (int i = 1; i <= N; i++) {
        viz[i] = 0;
    }
    DFS(ult,1);
    g << diam;
    f.close();
    g.close();
    return 0;
}