#include <bits/stdc++.h>
using namespace std;

int main()
{
	int n;
	cin >> n;
	vector<vector<int>> g(n);
	for (int i = 0; i < n - 1; i++)
	{
		int a, b;
		cin >> a >> b;
		a--;
		b--;
		g[a].emplace_back(b);
		g[b].emplace_back(a);
	}
	vector<int> dist(n, 1 << 30);
	dist[0] = 0;
	queue<int> q;
	q.emplace(0);
	while (!q.empty())
	{
		int x = q.front();
		q.pop();
		for (auto &next : g[x])
		{
			if (dist[x] + 1 < dist[next])
			{
				dist[next] = dist[x] + 1;
				q.emplace(next);
			}
		}
	}
	sort(dist.begin(), dist.end());
	reverse(dist.begin(), dist.end());
	cout << max(0, n - dist[0] - dist[1] - 1) << endl;
	return 0;
}