#include <bits/stdc++.h>
#define NMAX 100000

using namespace std;

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

int n, a, b;
int nod_1, nod_2, dist_max;
vector<int> arb[NMAX + 2];
vector<int> dist(NMAX + 2, 0), dist_2(NMAX + 2, 0);

void BFS(int start, vector<int> &d, int &nod_term) {
    queue<int> q;
    q.push(start);
    d[start] = 1;

    while (!q.empty()) {
        int nod = q.front();
        q.pop();
        for (int vec : arb[nod]) {
            if (!d[vec]) {
                d[vec] = d[nod] + 1;
                if (d[vec] > dist_max) {
                    dist_max = d[vec];
                    nod_term = vec;
                }
                q.push(vec);
            }
        }
    }
}

int main() {
    ios_base::sync_with_stdio(false);
    fin.tie(NULL);
    fout.tie(NULL);

    fin >> n;
    for (int i = 1; i <= n - 1; i++) {
        fin >> a >> b;
        arb[a].emplace_back(b);
        arb[b].emplace_back(a);
    }

    BFS(1, dist, nod_1);
    dist_max = 0;
    BFS(nod_1, dist_2, nod_2);

    fout << dist_max;
    return 0;
}