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

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

#define NMAX 100005

vector<int> A[NMAX];

int lung[NMAX];
queue<int> Q;

int bfs(int start, int n) {
    for (int i = 1; i <= n; ++i) {
        lung[i] = 0;
    }

    lung[start] = 1;
    Q.push(start);

    while (Q.size()) {
        int nod = Q.front();
        Q.pop();

        for (auto it : A[nod]) {
            if (lung[it] == 0) {
                lung[it] = lung[nod] + 1;
                Q.push(it);
            }
        }
    }

    int maxim = -1, capat;
    for (int i = 1; i <= n; ++i) {
        if (lung[i] > maxim) {
            maxim = lung[i];
            capat = i;
        }
    }

    return capat;
}

int main() {
    int n;
    fin >> n;
    for (int i = 1; i < n; ++i) {
        int a, b;
        fin >> a >> b;
        A[a].push_back(b);
        A[b].push_back(a);
    }

    int capat = bfs(1, n);
    capat = bfs(capat, n);

    fout << lung[capat];
    return 0;
}