#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint998244353;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf32 1000000001
#define Inf64 1000000000000000001
int ans = Inf32;

template <class Ss, Ss (*op0)(Ss, Ss), Ss (*e)(), class Sv, Ss (*op1)(Sv, Ss), class Se, Ss (*op2)(Se, Ss)>
struct rerooting{
	
	int n;
	vector<vector<int>> to;
	vector<vector<Se>> edge;
	
	vector<Ss> subtree,answer;
	
	vector<Sv> vertex;
	
	rerooting(int _n){
		n = _n;
		to.resize(n);
		edge.resize(n);
		subtree.resize(n,e());
		answer.resize(n,e());
		vertex.resize(n);
	}
	
	rerooting(vector<Sv> v){
		n = v.size();
		to.resize(n);
		edge.resize(n);
		subtree.resize(n,e());
		answer.resize(n,e());
		vertex = v;
	}
	
	void add_directed_edge(int u,int v,Se x){
		to[u].push_back(v);
		edge[u].push_back(x);
	}
	
	void add_edge(int u,int v,Se x){
		add_directed_edge(u,v,x);
		add_directed_edge(v,u,x);
	}
	
	void solve(){
		dfs(0,-1);
		redfs(0,-1,e());
	}
	
	void dfs(int cur,int par){
		Ss temp = e();
		for(int i=0;i<to[cur].size();i++){
			int nxt = to[cur][i];
			if(nxt==par)continue;
			dfs(nxt,cur);
			temp = op0(temp, op2(edge[cur][i], subtree[nxt]));
		}
		subtree[cur] = op1(vertex[cur], temp);
	}
	
	void redfs(int cur, int par, Ss ps){
		vector<Ss> P(to[cur].size()+1,e());
		rep(i,to[cur].size()){
			int nxt = to[cur][i];
			if(nxt!=par)P[i+1] = op2(edge[cur][i], subtree[nxt]);
			else P[i+1] = op2(edge[cur][i], ps);
		}
		{
			int tt= 0;
			rep(i,P.size()){
				tt += P[i].first;
			}
			ans = min(ans,tt+1);
		}
		vector<Ss> S(P.rbegin(),P.rend()-1);
		S.insert(S.begin(),e());
		rep(i,to[cur].size()){
			P[i+1] = op0(P[i], P[i+1]);
			S[i+1] = op0(S[i+1], S[i]);
		}
		answer[cur] = op1(vertex[cur], P.back());

		for(int i=0;i<to[cur].size();i++){
			int nxt = to[cur][i];
			if(nxt!=par){
				redfs(nxt,cur,op1(vertex[cur], op0(P[i],S[to[cur].size()-1-i])));
			}
		}
	}
	
};

using P = pair<int,int>;

P op0(P a,P b){
	return make_pair(max({a.first+b.first}),max({a.first+b.second,a.second+b.first,a.second+b.second}));
}

P e(){
	return make_pair(0,0);
}

P op1(int a,P b){
	return make_pair(max(b.first,b.second),b.first + 1);
}

P op2(int a,P b){
	return b;
}

int main(){
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	int n;
	cin>>n;
	rerooting<P,op0,e,int,op1,int,op2> R(n);
	rep(i,n-1){
		int a,b;
		cin>>a>>b;
		a--,b--;
		R.add_edge(a,b,0);
	}
	R.solve();
	cout<<ans<<endl;
	
	return 0;
}