import java.util.*;

/**
 * Created by tym16 on 10/22/16.
 */
public class Raining {
    private static final Scanner sc = new Scanner(System.in);

    public static void main(String[] args) {
        while (sc.hasNextInt()){
            int n = sc.nextInt();
            List<Karta> karta = new ArrayList<Karta>();
            for (int i = 0; i < n; i++){
                String k = sc.next();
                karta.add(new Karta(k.charAt(0), k.charAt(1)));
            }
            comparator(karta);
        }
    }

    public static void comparator(List<Karta> karta){
        Map<Integer, List<Karta>> map = new HashMap<>();
        for (int i = 1; i <= 17; i++){
            List<Karta> s = new ArrayList<Karta>();
            for(Karta k : karta){
                if(k.com(i)){
                    s.add(k);
                }
            }
            if(s.size() < 2){
                continue;
            }else{
                map.put(i, s);
            }
        }


        for(Karta k : karta){
            if(!(map.containsKey(k.getBarva()) || map.containsKey(k.getHodnota()))){
                System.out.println("NO");
                return;
            }
        }



        for (int i = 1; i <= 17; i++){
            if(!map.containsKey(i)){
                continue;
            }
            int pom = 0;
            for (int j = 1; j <= 17; j++){
                if(i == j ){
                    continue;
                }
                if(map.containsKey(j)){
                    for(Karta k : karta){
                        if(map.get(i).contains(k)){
                            pom++;
                        }
                    }
                }
            }
            if(pom < 2){
                System.out.println("NO");
                return;
            }
        }
        System.out.println("YES");

    }


    public static class Karta {
        char barva;
        int hodnota;

        public Karta(char h, char b){
            switch (h){
                case 'A':
                    hodnota = 1;
                    break;
                case 'X':
                    hodnota = 10;
                    break;
                case 'J':
                    hodnota = 11;
                    break;
                case 'Q':
                    hodnota = 12;
                    break;
                case 'K':
                    hodnota = 13;
                    break;
                default:
                    hodnota = Integer.parseInt(Character.toString(h));
                    break;
            }
            switch (b){
                case 'C':
                    barva = 14;
                    break;
                case 'D':
                    barva = 15;
                    break;
                case 'H':
                    barva = 16;
                    break;
                case 'S':
                    barva = 17;
                    break;
                default:
                    break;
            }
        }

        public int getBarva(){
            return barva;
        }

        public int getHodnota(){
            return hodnota;
        }

        public boolean com(int i){
            return i == barva || i == hodnota;
        }
    }
}