#include <bits/stdc++.h>

using namespace std;

int l;
const int L = 52;
bool vertices[L][L];

struct Card
{
    int index;
    char rank;
    char suit;
};
struct Card cards[L];
vector<int> currentCards;

void initCards()
{
    char ranks[] = {'A','2','3','4', '5', '6','7','8','9', 'X', 'J', 'Q', 'K'};
    char suits[] = {'C', 'D', 'H', 'S'};

    int index = 0;
    for(int suit = 0; suit < 4; suit++)
        for(int rank = 0; rank < 13; rank++)
        {
            cards[index].index = index;
            cards[index].rank = ranks[rank];
            cards[index].suit = suits[suit];
            //cout << "index= " << cards[index].rank << cards[index].suit << endl;
            index++;
        }
}

void initVertices()
{
    for(int i = 0; i < L; i++)
    {
        for(int j = 0; j < L; j++)
        {
            if(cards[i].rank == cards[j].rank ||
                    cards[i].suit == cards[j].suit)
                vertices[i][j] = vertices[j][i] = true;
        }
    }
}

void printCards()
{
    for(int i = 0; i < L; i++)
    {
        cout << "index= " << cards[i].rank << cards[i].suit << endl;
    }
}

void printVerticesMatrix()
{
    const int MAX_L = L;
    for(int i = 0; i < MAX_L; i++)
    {
        for(int j = 0; j < MAX_L; j++)
        {
            cout << vertices[i][j];
        }
        cout << endl;
    }
}

int getIndexForCard(char rank, char suit)
{
    for(int i = 0; i < L; i++)
        if(cards[i].rank == rank && cards[i].suit == suit)
            return i;

    //cout << "error" << endl;
    return -1;
}

int maxBfs = 0;

void bfs_inner(int card, int depth, bool visited[])
{
    if(visited[card])
        return;

    //cout << "visiting " << cards[card].rank << cards[card].suit << endl;
    visited[card] = true;
    maxBfs = max(depth, maxBfs);

    //int index = currentCards[i]; // index of currently iterated index
    //cout << "compare - " << cards[]


    for(int j = 0; j < l ; j++)
    {
        int index = currentCards[j];
        if(card == index)
            continue;
        if(vertices[card][index] == true)
        {
            bfs_inner(index, depth + 1, visited);
        }
    }

    //cout << "ending " << cards[card].rank << cards[card].suit << endl;
}

int bfs(int start)
{
    bool visited[L] = {};
    for(int i = 0; i < L; i++)
        visited[i] = false;

    maxBfs = 0;
    bfs_inner(currentCards[start],  1, visited);

    return maxBfs;

/*
    printf("\n");
    for(int i = 0; i < l; i++)
    {
        if (visited[currentCards[i]])
            printf("%c%c ", cards[i].rank, cards[i].suit);
    }
    printf("\n");

    int total = 0;
    for(int i = 0; i < l; i++)
        if(visited[i])
            total++;

    return total;
    */
}

int main()
{
    initCards();
    initVertices();
    //printVerticesMatrix();

    char rank, suit;
    while(cin >> l)
    {
        currentCards.clear();
        for(int i = 0; i < l; i++)
        {
            cin >> rank >> suit;
            //cout << "a=" << rank << suit << endl;
            currentCards.push_back(getIndexForCard(rank, suit));
        }

        int tmpMax = -1;
        int result = 0;
        for(int r = 0; r < l; r++)
        {
            result = bfs(r);
            if(result > tmpMax) tmpMax = result;
        }


        //cout << tmpMax << "\n";
        if(tmpMax == l)
            cout << "YES" << endl;
        else
            cout << "NO" << endl;
        //cout << result << endl;
    }
    return 0;
}