package yukicoder;

import java.util.Scanner;

public class Yuki29 {
	
	public static void main(String[] args) {
		
		int item[] = new int[12];
		Scanner scan = new Scanner(System.in);
		int mob_count = scan.nextInt();
		int getItem_arr[][] = new int[mob_count][3];
		for (int i = 0; i < mob_count; i++) {
			for (int j = 0; j < 3; j++) {
				getItem_arr[i][j] = scan.nextInt();	
				item[getItem_arr[i][j] + 1]++;
			}
		}
		scan.close();

		int power_up = 0;
		int remain_item = 0;
		for(int i = 1; i<=10; i++) {
			//System.out.println(item[i]);
			power_up += item[i]/2;
			remain_item += item[i]%2;
		}
		remain_item /= 4; 
		
		System.out.println(power_up + remain_item);
	}
}