package yukicoder;

import java.util.Scanner;

public class No_29v2 {
public static void main(String[] args) {
	int[] item = new int[11];
	Scanner sc = new Scanner(System.in);
	int N = sc.nextInt() * 3;
	for(int i = 0; i < N; i++){
		item[sc.nextInt()]++;
	}
	int C = 0;
	for(int i = 1; i <= 10; i++){
		if(item[i] >= 2){
			while(item[i] >= 2){
				item[i] -= 2;
				C++;
			}
		}
	}
	int PUC = 0;//Power UP Counting
	for(int i = 1; i <= 10; i++){
		if(PUC == 4){
			PUC = 0;
			C++;
		}
		if(item[i] >= 1){
			item[i] -= 1;
			PUC++;
		}
	}
	System.out.println(C);
}
}