#include <iostream>
#include <vector>
#include <utility>
#include <atcoder/segtree>
#include <assert.h>
using namespace atcoder;
using namespace std;

vector<vector<int>> Graph;
vector<bool> checked;

pair<int,int> op(pair<int,int> a,pair<int,int> b){
  return a>b?a:b;
}

pair<int,int> e(){
  return make_pair(-1,-1);
}

segtree<pair<int,int>,op,e> seg;
int searched=0;


int dfs(int i){
  int pre=searched;
  searched++;
  checked[i]=true;
  for(int to:Graph[i]){
    if(!checked[to]){
      seg.set(to,make_pair(dfs(to),to));
    }
  }
  int res=1;
  for(int j=0;j<2;j++){
    pair<int,int> tmp=seg.prod(pre,searched);
    if(tmp.first==-1){
      break;
    }
    res+=tmp.first;
    seg.set(tmp.second,e());
  }
  return res;
}

int main(){
  int N;
  cin>>N;
  Graph.resize(N);
  checked.resize(N,false);
  for(int i=0;i<N-1;i++){
    int x,y;
    cin>>x>>y;
    Graph[x-1].push_back(y-1);
    Graph[y-1].push_back(x-1);
  }
  seg=segtree<pair<int,int>,op,e>(N);
  int ans=dfs(0);
  cout<<ans<<endl;
  return 0;
}