package me.yukicoder;

import java.util.Scanner;

/**
 * http://yukicoder.me/problems/1
 */
public class YukiCoder29 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] items = new int[10];

        for (int i = 0; i < n; i++) {
            for (int j = 0; j < 3; j++) {
                items[sc.nextInt() - 1]++;
            }
        }

        int diffs = 0;
        int num = 0;
        for (int item : items) {
            num += item / 2;
            diffs += item % 2;
        }
        num += diffs / 4;

        System.out.println(num);
    }
}