#include <vector>
#include <unordered_map>
#include <unordered_set>
#include <iostream>

using namespace std;

const unordered_map<char, int> ranks = { {'2', 0}, 
										{'3', 1},
                           				{'4', 2},
										{'5', 3},
										{'6', 4},
										{'7', 5},
										{'8', 6},
										{'9', 7},
										{'X', 8},
										{'A', 9},
										{'J', 10},
										{'Q', 11},
										{'K', 12}};

const unordered_map<char, int> suits = { {'C', 0},
										{'D', 1},
										{'H', 2},
										{'S', 3}};

int card_id (char rank, char suit) {
	return ranks.at(rank)*4 + suits.at(suit);	
}

bool DFS(const unordered_set<int> & cards, uint64_t used, int from, int distance, const vector<vector<int>> & rank_adj, const vector<vector<int>> & suit_adj) {
	used|= (1u << from);
	if (distance == (int)(cards.size() - 1)) return true;
	//cout << "from " << from ;
	for (int i: rank_adj[from / 4] ) {
		if (i!=from) {
			if ((used & (1u << i)) ) {
				//cout << "go to  " << i;
				if (DFS(cards, used, i, distance+1, rank_adj, suit_adj)) return true;
			}			
		}
	}
	for (int i: suit_adj[from % 4]) {
		if (i!=from) {
			if ((used & (1u << i))) {
				//cout << "go to  " << i;
				if (DFS(cards, used, i, distance+1, rank_adj, suit_adj)) return true;
			}			
		}
	}
	return false;
}

int main () {
	ios::sync_with_stdio(false);
	for(;;) {
		int n; cin >> n;
		if (cin.eof()) break;
		
		unordered_set<int> cards;
		vector<vector<int>> rank_adj(13);
		vector<vector<int>> suit_adj(4);
		for (int i = 0; i < n; i++) {
			char r, s;
			cin >> r >> s;
			//cout << r << s << card_id(r, s) << '\n';
			int id = card_id(r, s);
			cards.insert(id);
			rank_adj[id / 4].push_back(id);
			suit_adj[id % 4].push_back(id);
		}
		
		if (n == 1) {
			cout << "NO\n";
			continue;
		}
		
	
		
		bool flag = false;
		for (int from: cards) {
			//cout << "start at" << from << '\n';
			if (DFS(cards, 0, from, 0, rank_adj, suit_adj)) {
				cout << "YES\n";
				flag = true;
				break;
			}
			
		}
		if (!flag) {
			cout << "NO\n";
			continue;
		}
	}
	return 0;
}