#include <fstream>
#include <vector>
using namespace std;
ifstream cin("darb.in");
ofstream cout("darb.out");
vector < int > E[100005];
vector < int > D(100005, 0);
int n, x, y, far_node, mx = 0;
void Dfs(int x, int prev)
{
    D[x] = D[prev] + 1;
    for (auto it : E[x])
    if (it != prev) Dfs(it, x);
}
int main()
{
    cin >> n;
    for (int i = 1; i < n; i++)
    {
        cin >> x >> y;
        E[x].push_back(y);
        E[y].push_back(x);
    }
    D[0] = 0;
    Dfs(1, 0);
    for (int i = 1; i <= n; i++)
    if (D[i] > mx) mx = D[i], far_node = i;
    D.clear();
    D[0] = 0;
    Dfs(far_node, 0);
    mx = 0;
    for (int i = 1; i <= n; i++) if (D[i] > mx) mx = D[i];
    cout << mx;
    return 0;
}