#include <fstream>
#include <vector>

using namespace std;

const int NMAX = 1e5 + 5;

ifstream cin("darb.in");
ofstream cout("darb.out");

vector <int> g[NMAX];
int st = 0;
int maxim = -1;

void dfs(int node, int father, int d)
{
    if(d > maxim) {
        maxim = d;
        st = node;
    }
    for(auto x: g[node]) {
        if(x != father) {
            dfs(x, node, d + 1);
        }
    }
}

int main()
{
    int n;
    cin >> n;
    for(int i = 1; i < n; ++i) {
        int x, y;
        cin >> x >> y;
        g[x].push_back(y);
        g[y].push_back(x);
    }
    dfs(1, -1, 0);
    maxim = -1;
    dfs(st, -1, 1);
    cout << maxim << "\n";
    return 0;
}