import java.util.*;
public class Powerup{
	public static void main(String[] arg){
		int[] item = {0,0,0,0,0,0,0,0,0,0};
		int n,m,res = 0,count = 0;
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		for(int i = 0;i<n;i++){
			for(int j = 0;j<3;j++){
				m = sc.nextInt();
				item[m-1]=item[m-1]+1;
			}
		}
		for(int i = 0;i<10;i++){
			while(item[i]>1){
				item[i] = item[i]-2;
				res++;
			}
			if(item[i] == 1)count++;
		}
		res = res + (count /4);
		System.out.println(res);
	}
}