#include <bits/stdc++.h>

using namespace std;
using LL = long long;
const LL LINF = 1e18;
class Edge{
public:
    int to,from,value;
    Edge(int t,int f,int c){
        to = t;
        from = f;
        value = c;
    }
};
#define P pair<LL,LL>
std::vector<LL> dijkstra(int s,int N,vector<Edge> E){
    std::vector<LL> ans(N,LINF);
    std::vector<std::vector<Edge>> Edges(N);
    for(auto e : E){
        Edges.at(e.from).push_back(e);
    }
    priority_queue<P, std::vector<P>, greater<P>> que;
    ans.at(s)= 0;
    que.push(make_pair(0,s));
    while(!que.empty()){
        P p = que.top();que.pop();
        if(ans.at(p.second) < p.first)continue;
        for(int i = 0;i < Edges.at(p.second).size();i++){
                if(ans.at(p.second) + Edges.at(p.second).at(i).value < ans.at(Edges.at(p.second).at(i).to)){
                ans.at(Edges.at(p.second).at(i).to) = ans.at(p.second) + Edges.at(p.second).at(i).value;
                que.push(make_pair(ans.at(Edges.at(p.second).at(i).to),Edges.at(p.second).at(i).to));
            }
        }
    }
    return ans;
}
int main(){
    int N;cin >> N;
    vector<Edge> Edges;
    for(int a = 0;a < N-1;a++){
        int b,c;cin >> b >> c;
        Edges.push_back(Edge(b-1,c-1,1));
        Edges.push_back(Edge(c-1,b-1,1));
    }
    vector<LL> di = dijkstra(0,N,Edges);
    int idx = max_element(di.begin(),di.end())-di.begin();
    vector<LL> ansns = dijkstra(idx,N,Edges);
    cout<<N-*max_element(ansns.begin(),ansns.end())-1<<endl;;
}