using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace lecture
{
    class Program
    {

        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            int[] a = new int[N];
            int[] b = new int[N];
            int[] c = new int[N];

            for (int i = 0; i < N; i++)
            {
                int[] line = Console.ReadLine().Trim().Split(' ').Select(x => int.Parse(x)).ToArray();
                a[i] = line[0];
                b[i] = line[1];
                c[i] = line[2];
            }
            int[] data = new int[11];
            for (int i = 1; i <= 10; i++)
            {
                for (int j = 0; j < N; j++) 
                {
                    if (a[j] == i) { data[i]++; }
                    if (b[j] == i) { data[i]++; }
                    if (c[j] == i) { data[i]++; }
                }
            }
            int result = 0;
            int amari = 0;
            for(int i = 1;i <= 10;i++)
            {
                result += data[i] / 2;
                amari += data[i] % 4;
            }
            Console.WriteLine(result + amari / 4);

 


        }
    }
}