#include <iostream>
#include <vector>
using namespace std;
const int N = 1e5 + 10;
vector<int> g[N];
int vis[N];
int ans = -1e9;
void dfs(int u, int fa, int step) {
	vis[u] = 1;
	if (g[u].size() == 0) {
		ans = max(ans, step);
		return ;
	}
	for (auto v : g[u]) {
		if (!vis[v] && v != fa) {
			dfs(v, u, step + 1);
		}
	}
}
int main()
{
	int n;
	cin >> n;
	for (int i = 1; i < n; i++) {
		int u, v;
		cin >> u >> v;
		g[u].push_back(v);
	}
	dfs(1, 0, 0);
	cout << ans;
	return 0;
}