import java.util.Scanner;

public class No29 {

    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++) {
            int[] gets = new int[3];
            for (int j = 0; j < gets.length; j++) {
                gets[j] = sc.nextInt() - 1;
            }

            for (int j = 0; j < gets.length; j++) {
                items[gets[j]]++;
            }
        }

        int powerUpCnt = 0;

        for (int i = 0; i < items.length; i++) {
            powerUpCnt += items[i] / 2;
            items[i] = items[i] % 2;
        }

        while (canPowerUp(items)) {
            int cnt = 0;

            for (int i = 0; i < items.length; i++) {
                if (items[i] > 0) {
                    cnt++;
                    items[i]--;

                    if (cnt >= 4) {
                        powerUpCnt++;
                        break;
                    }
                }
            }
        }

        System.out.println(powerUpCnt);

        sc.locale();
    }

    private static boolean canPowerUp(int[] items) {
        int cnt = 0;

        for (int val : items) {
            if (val > 0) {
                cnt++;
            }
        }

        if (cnt >= 4) {
            return true;
        } else {
            return false;
        }
    }

}