import java.util.Scanner;

public class No0029 {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		char[] num = new char[10];
		for(int i=0; i<n; i++){
			for(int j=0; j<3; j++){
				int data = sc.nextInt();
				num[data-1] ++;
			}
		}
		sc.close();
		int cnt1 = 0;
		int cnt2 = 0;
		for(int i=0; i<10; i++){
			cnt1 += num[i] / 2;
			cnt2 += num[i] % 2;
		}
		int ans = cnt1 + (cnt2 / 4);
		System.out.println(ans);
	}
}