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

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

const int NMAX = 1e5+5;
vector<int> graf[NMAX];
int dist[NMAX];

void bfs(int nod) {
    dist[nod] = 1;
    queue<int> coada;
    coada.push(nod);
    while(!coada.empty()) {
        nod = coada.front();
        coada.pop();
        for(int i = 0; i < (int)graf[nod].size(); i++) {
            int next = graf[nod][i];
            if(!dist[next]) {
                dist[next] = dist[nod] + 1;
                coada.push(next);
            }
        }
    }
}

int main()
{
    int n;
    f >> n;
    for(int i = 1; i <= n - 1; i++) {
        int x, y;
        f >> x >> y;
        graf[x].push_back(y);
        graf[y].push_back(x);
    }
    bfs(1);
    int maxim = 0;
    int nod = 1;
    for(int i = 1; i <= n; i++) {
        if(dist[i] > maxim) {
            maxim = dist[i];
            nod = i;
        }
    }
    for(int i = 1; i <= n; i++) {
        dist[i] = 0;
    }
    bfs(nod);
    maxim = 0;
    for(int i = 1; i <= n; i++) {
        maxim = max(maxim, dist[i]);
    }
    g << maxim;
    return 0;
}