import java.util.Scanner;

class Y29{
    public static void main(String args[]){
        Scanner sc=new Scanner(System.in);
        int n=sc.nextInt();
        int[] item=new int[11];
        for(int i=0;i<n*3;i++){
            item[sc.nextInt()]++;
        }
        int count=0;
        int ans=0;
        for(int i=1;i<=10;i++){
            ans+=item[i]/2;
            count+=item[i]%2;
        }
        ans+=count/4;
        System.out.println(ans);
    }
}