#include <iostream>
#include <list>

using namespace std;

struct Card {
    Card(): visited(false) {};
    list<Card*> connect;
    bool visited;
};

struct CardItem {
    CardItem(): depth(0), prev(nullptr) {};

    Card* card;
    int depth;
    CardItem* prev;
};

int numberToIndex(char n) {
    if (n >= '2' && n <= '9') {
        return n - '2';
    }
    switch(n) {
        case 'X': return 8;
        case 'J': return 9;
        case 'Q': return 10;
        case 'K': return 11;
        case 'A': return 12;
    }
    cout << "error!" << (int)n << endl;
}

int colorToIndex(char n) {
    switch (n) {
        case 'C': return 0;
        case 'D': return 1;
        case 'H': return 2;
        case 'S': return 3;
    }
    cout << "error2!" << n << endl;
}



int main()
{

    Card start;
    while (true) {
        string line;
        list<Card*> numbersList[13];
        list<Card*> colorsList[4];
        list<Card*> toBeDeletedCards;
        list<Card*> cardsToTry;

        int cards;
        if (!(cin >> cards))
            break;

        int expectedDepth = -1;
        for (int i = 0; i < cards; ++ i) {
            char number, color;
            string nc;
            cin >> nc;

            number = nc[0];
            color = nc[1];
            //cout << (char)number << ", " << color << endl;


            Card* newCard = new Card();
            toBeDeletedCards.push_back(newCard);
            // connect all relevant
            for (auto j = numbersList[numberToIndex(number)].begin(); j != numbersList[numberToIndex(number)].end(); ++ j) {
                newCard->connect.push_back(*j);
                (*j)->connect.push_back(newCard);
            }
            for (auto j = colorsList[colorToIndex(color)].begin(); j != colorsList[colorToIndex(color)].end(); ++ j) {
                newCard->connect.push_back(*j);
                (*j)->connect.push_back(newCard);
            }
            expectedDepth ++;

            // insert the card
            numbersList[numberToIndex(number)].push_back(newCard);
            colorsList[colorToIndex(color)].push_back(newCard);
            cardsToTry.push_back(newCard);
        }
        if (expectedDepth == 0) {
            cout << "YES" << endl;
            continue;
        }

        bool found = false;
        for (auto startCard = cardsToTry.begin(); startCard != cardsToTry.end(); ++ startCard) {


            // bfs
            CardItem root;
            root.card = (*startCard);
            list<CardItem*> cardQueue;
            cardQueue.push_back(&root);
            list<CardItem*> toBeDeleted;
            root.card->visited = true;

            for (auto x = cardsToTry.begin(); x != cardsToTry.end(); ++ x) {
                (*x)->visited = false;
            }


            while (!cardQueue.empty()) {
                CardItem* curCard = cardQueue.front();
                cardQueue.pop_front();

                //cout << curCard->depth << endl;

                for (auto i = curCard->card->connect.begin(); i != curCard->card->connect.end(); ++ i) {
                    bool isVisited = false;
                    CardItem* curCardItem = curCard;
                    while (curCardItem != nullptr) {
                        if (curCardItem->card == (*i)) {
                            isVisited = true;
                            break;
                        }
                        curCardItem = curCardItem->prev;
                    }
                    if (!isVisited) {
                        (*i)->visited = true;
                        CardItem* newItem = new CardItem();
                        newItem->prev = curCard;
                        newItem->depth = curCard->depth + 1;
                        newItem->card = (*i);

                        if (newItem->depth == expectedDepth) {
                            cout << "YES" << endl;
                            found = true;
                            break;
                        }

                        cardQueue.push_back(newItem);
                        toBeDeleted.push_back(newItem);

                    }
                }
                if (found) break;
            }
            for (auto j = toBeDeleted.begin(); j != toBeDeleted.end(); ++ j) {
                delete (*j);
            }
            if (found) break;
        }
        if (!found) {
            cout << "NO" << endl;
        }
        for (auto j = toBeDeletedCards.begin(); j != toBeDeletedCards.end(); ++ j) {
            delete (*j);
        }


    }
    return 0;
}