#include <bits/stdc++.h>
#define REP(i, n) for(int i = 0;i < n;i++)
#define REPR(i, n) for(int i = n;i >= 0;i--)  
#define FOR(i, m, n) for(int i = m;i < n;i++)
#define FORR(i, m, n) for(int i = m;i >= n;i--)
#define SORT(v, n) sort(v, v+n);
#define VSORT(v) sort(v.begin(), v.end());
#define llong long long
#define pb(a) push_back(a)
#define INF 999999999
using namespace std;
typedef pair<int, int> P;
typedef pair<llong, llong> LP;
typedef pair<int, P> PP;
typedef pair<llong, LP> LPP;

int dy[]={0, 0, 1, -1};
int dx[]={1, -1, 0, 0};

int main(){


  int n;
  cin>>n;
  vector<int> v[n];
  REP(i,n-1){
    int a,b;
    cin>>a>>b;
    a--;
    b--;
    v[a].pb(b);
    v[b].pb(a);
  }

  int kyori[n];
  REP(i,n){
    kyori[i] = -1;
  }
  queue<int> q;
  q.push(0);
  kyori[0] = 0;
  while(!q.empty()){
    int t = q.front();
    q.pop();
    REP(i,v[t].size()){
      if(kyori[v[t][i]] == -1){
        kyori[v[t][i]] = kyori[t] +1;
        q.push(v[t][i]);
      }
    }
  }

  int king,queen;
  king = 0;
  queen = 0;
  REP(i,n){
    if(kyori[i]>=king){
      queen = king;
      king = kyori[i];
    }
  }

  int saicho = king + queen + 1;
  cout<<n - saicho<<endl;

 

  return 0;
}