import java.util.*;

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