#include <bits/stdc++.h>
using namespace std;
#define int long long
#define rep(i,j)  for(int i=0; i<j; i++)
#define vi vector<int>
#define vvi vector<vector<int>>
#define sr(a) sort(a.begin(),a.end())

signed main(){
  int n; cin>>n; vi b(10); int sum;
  rep(i,n*3){
    int a; cin>>a;
    if(b[a-1]==0){
      b[a-1]=1;
    }
    else{
      sum++;
      b[a-1]=0;
    }
  }
  sum+=(n*3-sum*2)/4;
  cout<<sum<<endl;
}