import java.util.Arrays;
import java.util.LinkedList;
import java.util.Scanner;

public class Main {
	
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		
		final int SIZE = 10;
		
		final int N = sc.nextInt();
		
		int[] items = new int[SIZE];
		for(int i = 0; i < N; i++){
			final int a = sc.nextInt() - 1;
			final int b = sc.nextInt() - 1;
			final int c = sc.nextInt() - 1;
			
			items[a]++;
			items[b]++;
			items[c]++;
		}
		
		int answer = 0;
		for(int i = 0; i < SIZE; i++){
			answer += items[i] / 2;
			items[i] %= 2;
		}
		
		int sum = 0;
		for(int i = 0; i < SIZE; i++){
			sum += items[i];
		}
		
		answer += sum / 4;
		
		System.out.println(answer);
		
		
	}
	
}