import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int[] ar = new int[11];
		int times = 0;
		int n = sc.nextInt();
		for (int i=0; i<n; i++) {
			int a = sc.nextInt();
			int b = sc.nextInt();
			int c = sc.nextInt();
			ar[a]++;
			ar[b]++;
			ar[c]++;
		}
		
		for (int i=0; i<ar.length; i++) {
			if (ar[i]>=2) {
				int temp = ar[i]/2;
				times += temp;
				ar[i] -= temp*2;
			}
		}
		
		
		
		int sum = 0;
		for (int i=0; i<ar.length; i++) {
			sum += ar[i];
		}
		System.out.println(times+(sum/4));
	}
}