#include <iostream>
#include <vector>

using namespace std;

int n;
vector<int> G[100005];
int dist[100005];

void dfs(int v, int pre, int d)
{
	dist[v] = d;
	for(int i = 0; i < G[v].size(); i++){
		if(G[v][i] == pre) continue;
		dfs(G[v][i], v, d+1);
	}
}

int main(void)
{
	cin >> n;
	int u, v;
	for(int i = 0; i < n-1; i++){
		cin >> u >> v;
		G[u].push_back(v);
		G[v].push_back(u);
	}
	
	dfs(1, -1, 0);
	int mx = 0, root;
	for(int i = 1; i <= n; i++){
		if(mx < dist[i]){
			mx = dist[i];
			root = i;
		}
	}
	
	dfs(root, -1, 0);
	int dia = 0;
	for(int i = 1; i <= n; i++) dia = max(dia, dist[i]);
	
	cout << (n-1) - dia << endl;
	return 0;
}