using System;

public class Hello
{
    public static void Main()
    {
        var n = int.Parse(Console.ReadLine().Trim());
        var item = new int[10];
        for (int i = 0; i < n; i++)
        {
            string[] line = Console.ReadLine().Trim().Split(' ');
            for (int j = 0; j < 3; j++)
                item[int.Parse(line[j]) - 1]++;
        }
        var count = 0;
        var sum = 0;
        for (int i = 0; i < 10; i++)
        {
            count += item[i] / 2;
            item[i] %= 2;
            sum += item[i];
        }
        count += sum / 4;
        Console.WriteLine(count);
    }
}