import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	}
} Main public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	} main {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String[] w = new String[n]; w new String[n] n String msg = "Yes"; msg "Yes" for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			w[i] = sc.next();
		} {
			w[i] = sc.next();
		} w[i] = sc.next() w[i] w i sc.next() sc.next sc for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		} {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		} if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			} !(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1))) (w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1))) w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals w[i-1].substring(w[i-1].length() - 1, w[i-1].length()) w[i-1].substring w[i-1] w i-1 i 1 w[i-1].length() - 1 w[i-1].length() w[i-1].length w[i-1] w i-1 i 1 1 w[i-1].length() w[i-1].length w[i-1] w i-1 i 1 w[i].substring(0, 1) w[i].substring w[i] w i 0 1 {
				msg = "No";
				break;
			} msg = "No" msg "No" break; for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			} int j = 0; int j = 0; j 0 j < i j i j++ j++ j {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			} {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			} if (w[j].equals(w[i])) {
					msg = "No";
					break;
				} w[j].equals(w[i]) w[j].equals w[j] w j w[i] w i {
					msg = "No";
					break;
				} msg = "No" msg "No" break; System.out.println(msg) System.out.println System.out System System.out msg String[] args args public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	}
} public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	}
} Main
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String[] w = new String[n];
		String msg = "Yes";

		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
		}

		for (int i = 1; i < n; i++) {
			if (!(w[i-1].substring(w[i-1].length() - 1, w[i-1].length()).equals(w[i].substring(0, 1)))) {
				msg = "No";
				break;
			}

			for (int j = 0; j < i; j++) {
				if (w[j].equals(w[i])) {
					msg = "No";
					break;
				}
			}
		}

		System.out.println(msg);

	}
}