#include<bits/stdc++.h>
#define INF 1e9
#define llINF 1e18
#define MOD 1000000007
#define pb push_back
#define mp make_pair 
#define F first
#define S second
#define ll long long
#define ull unsigned long long
#define vi vector<ll>
#define vvi vector<vi>
#define DBG_N(hoge) cerr<<"!"<<" "<<(hoge)<<endl;
#define DBG cerr<<"!"<<endl;
#define BITLE(n) (1LL<<((ll)n))
#define BITCNT(n) (__builtin_popcountll(n))
#define SUBS(s,f,t) ((s).substr((f)-1,(t)-(f)+1))
#define ALL(a) (a).begin(),(a).end()
using namespace std;
vvi E(111111);
ll po=0;
ll leng=0;
bool vis[111111];
void dfs(ll now,ll len){
  if(len>leng){
    leng=len;
    po=now;
  }
  for(auto a:E[now]){
    if(vis[a]==false){
      vis[a]=true;
      dfs(a,len+1);
    }
  }
}
int main(){
  cin.tie(0);
  ios::sync_with_stdio(false);
  ll n;cin>>n;
  for(int i=0;i<n-1;i++){
    ll a,b;cin>>a>>b;
    --a;--b;
    E[a].pb(b);
    E[b].pb(a);
  }
  vis[0]=true;
  dfs(0,0);
  leng=0;
  for(int i=0;i<111111;i++)vis[i]=false;
  dfs(po,0);
  cout<<n-1-leng<<endl;
  return 0;
}