import java.util.*;
import java.lang.*;
import java.io.*;

class Main
{
	public static void main (String[] args) 
	{
		// 入力値の読み込み
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<String> a=new ArrayList<>();
		for(int i=0;i<3*n;i++){
			a.add(sc.next());
		}
		
		int two=0;
		int ans =0;
		
		// カウント
		TreeSet<String> b=new TreeSet<>(a);
		
		
		for(String s:b){
			int coun=0;
			for(String c:a){
				if(s.equals(c))coun++;
			}
			if(coun >= 2){
				two += coun/2;
			}
		}
		
		ans = two + (3*n-2*two)/4;
		
		System.out.println(ans);
	}
}