#include<iostream>
#include<algorithm>
#include<vector>
#include<queue>
using namespace std;

int main(){
    int N;
    cin >> N;
    vector<vector<int>> G(N);
    vector<bool> visited(N,false);

    for(int i=0;i<N-1;i++){
        int a,b;
        cin >> a >> b;
        a--, b--;
        G[a].push_back(b);
        G[b].push_back(a);
    }

    queue<pair<int,int>> Q;
    Q.push({0,0});

    int dia = 0;
    while(!Q.empty()){
        pair<int,int> p = Q.front();
        Q.pop();

        for(int to : G[p.first]){
            if(visited[to]) continue;
            visited[to] = true;
            dia = max(dia,p.second+1);
            Q.push({to,p.second+1});
        }
    }

    cout << N-dia-1 << endl;

}