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

#define MAXN 100005
#define inf 0x3f3f3f3f

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

int n;
vector<int> G[MAXN];
queue<int> q;
int dist[MAXN];

void bfs(int nod) {
    memset(dist, 0x3f, sizeof(dist));

    q.push(nod);
    dist[nod] = 0;
    while (!q.empty()) {
        int nd = q.front();
        q.pop();

        for (int i = 0; i < G[nd].size(); i++) {
            if (dist[G[nd][i]] == inf) {
                dist[G[nd][i]] = dist[nd] + 1;
                q.push(G[nd][i]);
            }
        }
    }
}

int main()
{
    f >> n;
    for (int i = 1; i < n; i++) {
        int x, y;
        f >> x >> y;
        G[x].push_back(y);
        G[y].push_back(x);
    }

    bfs(1);

    int mx = 0, p = 1;
    for (int i = 1; i <= n; i++) {
        if (mx < dist[i]) {
            mx = dist[i];
            p = i;
        }
    }

    bfs(p);

    mx = 0;
    for (int i = 1; i <= n; i++) {
        mx = max(mx, dist[i]);
    }
    g << mx + 1 << endl;

    return 0;
}