import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int [] item = new int [10];
        for(int i=0; i<N; i++){
            int a = sc.nextInt();
            item[a-1]+=1;
            int b = sc.nextInt();
            item[b-1]+=1;
            int c = sc.nextInt();
            item[c-1]+=1;
        }
        int c=0;
        int s=0;
        for(int i=0; i<10; i++){
            c = c + item[i]/2 ;
            s = s + item[i]%2 ;
        }
        int r = c + s/4 ;
        System.out.println(r);
    }
}