using System;

namespace No._29
{
    class Program
    {
        static void Main(string[] args)
        {
            int N = int.Parse(Console.ReadLine());
            int[,] a = new int[N,3];
            int[] item = new int[11];
            int powerUp = 0;
            int remain = 0;

            for (int i = 0; i < N; i++)
            {
                string[] buff = Console.ReadLine().Split();
                a[i, 0] = int.Parse(buff[0]);
                a[i, 1] = int.Parse(buff[1]);
                a[i, 2] = int.Parse(buff[2]);
            }

            for (int i = 0; i < N; i++)
            {
                for (int j = 0; j < 3; j++)
                {
                    item[a[i, j]]++;
                }
            }

            for (int i = 1; i <= 10; i++)
            {
                powerUp += item[i] / 2;
                remain += item[i] % 2;
            }

            powerUp += remain / 4;

            Console.WriteLine(powerUp);
        }
    }
}