#include<bits/stdc++.h>

using namespace std;
using ll = long long;

vector<int> BFS(vector<vector<int>> Hen, int s) {
	const int INF = 1e9;
	int n = Hen.size();
	vector<int> dist(n, INF);
	queue<int> que;
	dist[s] = 0;
	que.push(s);
	while(que.size()) {
		auto cur = que.front(); que.pop();
		for(auto i : Hen[cur]) {
			if(dist[i] != INF)continue;
			dist[i] = dist[cur] + 1;
			que.push(i);
		}
	}
	return dist;
}


int diameter(vector<vector<int>>(hen)) {
	auto dist = BFS(hen, 0);
	int idx = max_element(dist.begin(),dist.end()) - dist.begin();
	dist = BFS(hen, idx);
	return *max_element(dist.begin(), dist.end());
}

int main()
{
	int n;
	cin >> n;
	vector<vector<int>> hen(n);
	for(int i = 0; i < n - 1; i++) {
		int a, b; cin >> a >> b;
		a--, b--;
		hen[a].emplace_back(b);
		hen[b].emplace_back(a);
	}
	cout << n-1 - diameter(hen) << endl;
}