import java.util.Arrays;
import java.util.Scanner;


public class Example2 {

    private static int[] col;
    private static int count = 1;
    private static int superCount = 0;

    public static void main(String[] args) {
        try {
            Scanner scanner = new Scanner(System.in);
            int a = scanner.nextInt();
            if (a>=0 && a<=150){
                col = new int[a];
                for (int i = 0; i < a; i++) {
                    col[i]=scanner.nextInt();
                    if(col[i]<600 || col[i]>700){
                        //System.out.print("0");
                        throw new Exception();
                    }
                }
                Arrays.sort(col);
                for (int i = 1; i < col.length; i++) {
                    if (col[i]==col[i-1]) {
                        count ++;
                        if (count==4) {
                            superCount ++;
                            count=1;
                        }
                    }else count=1;
                }
                System.out.print(superCount);
            }else if (a>=0){System.out.print("0");}
        } catch (Exception e) {}
    }

}