import java.util.*;

public class Yukicoder_29{
	public static void main(String[] args){
		Scanner stdIn = new Scanner(System.in);
		int N = stdIn.nextInt();
		int[] num = new int[11];

		for(int i=0;i<N;i++){
			int a = stdIn.nextInt();
			int b = stdIn.nextInt();
			int c = stdIn.nextInt();
			num[a]++;
			num[b]++;
			num[c]++;
		}
		int count = 0;
		for(int i=1;i<11;i++){
			while(num[i]>=2){
				num[i] = num[i] - 2;
				count++;
			}
		}
		int counter = 0;
		for(int i=1;i<11;i++){
			counter += num[i];
		}
		count += counter/4;

		System.out.println(count);

	}

}