import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] items = new int[11];
        for (int i = 0; i < n * 3; i++) {
            items[sc.nextInt()]++;
        }
        int ans = 0;
        int count = 0;
        for (int i = 1; i <= 10; i++) {
            ans += items[i] / 2;
            count += items[i] % 2;
        }
        ans += count / 4;
        System.out.println(ans);
    }
}