import java.util.ArrayList;
import java.util.Collections;

/**
 * Created by Ekuseru on 2015/04/26.
 */
public class HappyFamily {

    public static void main(String[] args){
        String[] family ={"A", "B", "C","D","E","F"};
        String[] job = {" 1", "\'2", "\'3", "\'4"};
        int count = 0;

        ArrayList<String> deck = new ArrayList<String>();
        for (int i = 0; i < family.length; i++) {
            for (int j = 0; j < job.length; j++) {
                deck.add(family[i] + job[j]);
            }
        }

        //draw random 10 cards
        ArrayList<String> hand = new ArrayList<String>();
        Collections.shuffle(deck);
        for (int i = 0; i < 20; i++) {
            hand.add(deck.get(0));
            deck.remove(0);
        }

        Collections.sort(hand);
        String[] h = hand.toArray(new String[hand.size()]);
        hand.toArray(h);
        for(int i=0; i<h.length-4;i++){
            String t1 = h[i];
            String t2 = h[i+3];
            t1 = t1.split("('|\\s)")[0];
            t2 = t2.split("('|\\s)")[0];
            count = t1.equals(t2)?count+1: count;
        }

        System.out.println(count);
    }
}