package yukicoder029;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
	public static void main(String[] args){
		Scanner sc=new Scanner(System.in);
		int[] memo=new int[10];
		int n=sc.nextInt();
		for(int i=0;i<n;i++){
			for(int j=0;j<3;j++){
				memo[sc.nextInt()-1]++;
			}
		}
		Arrays.sort(memo);
		int count=0;
		int res=0;
		for(int i=0;i<10;i++){
			count+=memo[i]/2;
			memo[i]-=memo[i]/2*2;
			res+=memo[i];
		}
		count+=res/4;
		System.out.println(count);
	}
}