import java.util.*;

public class Main {
    private static Scanner sc = new Scanner(System.in);
    public static void main(String[] args) throws Exception {
        int[] item = new int[11];
        int n = sc.nextInt();
        for (int i = 0;i < n;i++) {
            for (int j = 0;j < 3;j++) {
                item[sc.nextInt()]++;
            }
        }
        int ret = 0;
        int mod = 0;
        for (int i = 1;i <= 10;i++) {
            int val = item[i];
            ret += val/2;
            mod += val%2;
        }
        ret += mod/4;
        System.out.println(ret);
    }
}