using System;
public class Program
{
    public static void Main()
    {
        int enemy = int.Parse(Console.ReadLine() ?? string.Empty);
        //string[] pass = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
        //string a = Console.ReadLine() ?? string.Empty;

        List<int> list = new List<int>();

        for (int i = 0; i < enemy; i++)
        {
            string[] item = (Console.ReadLine() ?? string.Empty).Trim().Split(' ');
            list.Add(int.Parse(item[0]));
            list.Add(int.Parse(item[1]));
            list.Add(int.Parse(item[2]));
        }

        int count = 0;
        for(int i = 0;i < list.Count;i++)
        {

            int index = list.LastIndexOf(list[i]);
            if(index == i ||  index == -1)
            {
                continue;
            }
            count++;
            list.RemoveAt(i);
            list.RemoveAt(index-1);
            i = -1;
        }
        if(list.Count >= 4)
        {
            count += list.Count / 4;
        }
        Console.WriteLine(count);

    }
}