import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        int n = koko.nextInt();
        int[] b = new int[n*3];
        int[] item = new int[10];
        for(int i=0; i<n*3; i++){
            b[i] = koko.nextInt();
            item[b[i]-1]++;
        }
        int amari = 0;
        int count = 0;
        int m;
        for(int i=0; i<10;i++){
            m = item[i]%2;
            count = count + ((item[i]-m)/2);
            amari = amari + m;
        }
        int mm = amari%4;
        count = count + ((amari-mm)/4);
        System.out.println(count);
    }
}