import java.util.Scanner;


public class Main_yukicoder29 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int n = sc.nextInt();
        int[] nn = new int[10];
        for (int i = 0; i < n; i++) {
        	for (int j = 0; j < 3; j++) {
        		int a = sc.nextInt() - 1;
        		nn[a]++;
        	}
        }

        int ret = 0;
        int tmp = 0;
        for (int i = 0; i < 10; i++) {
        	ret += nn[i] / 2;
        	tmp += nn[i] % 2;
        }
        ret += tmp / 4;
        
		System.out.println(ret);

		sc.close();
    }
}