#include <fstream>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;

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

const int MAXN = 100005;
int n;
vector<int> v[MAXN];

bool viz[MAXN];
int last, maxx, care;

void dfs(int k, int d) {
    viz[k] = 1;
    last = k;
    if (maxx < d) {
        maxx = d;
        care = k;
    }
    for (int i = 0; i < v[k].size(); ++i) {
        if (viz[v[k][i]] == 0) {
            dfs(v[k][i], d + 1);
        }
    }
}

int main() {

    fin >> n;
    for (int i = 1; i < n; ++i) {
        int a, b;
        fin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    dfs(1, 1);
    for (int i = 1; i <= n; ++i) {
        viz[i] = 0;
    }
    maxx = 0;
    dfs(care, 1);
    fout << maxx;

    fout.close();
    return 0;
}