import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	}

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

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	}

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

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	} main {

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	} Scanner scanner = new Scanner(System.in); scanner new Scanner(System.in) String temp = scanner.nextLine(); temp scanner.nextLine() scanner.nextLine scanner int n = Integer.parseInt(temp); n Integer.parseInt(temp) Integer.parseInt Integer temp int flag = 0; flag 0 String[] list = new String[n]; list new String[n] n for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		} {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		} list[i] = scanner.nextLine() list[i] list i scanner.nextLine() scanner.nextLine scanner if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			} i != 0 i 0 {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			} if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				} list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1) list[i].charAt(0) list[i].charAt list[i] list i 0 list[i - 1].charAt(list[i - 1].length() - 1) list[i - 1].charAt list[i - 1] list i - 1 i 1 list[i - 1].length() - 1 list[i - 1].length() list[i - 1].length list[i - 1] list i - 1 i 1 1 {
					flag++;
					break;
				} flag++ flag break; for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			} int j = 0; int j = 0; j 0 j < i j i j++ j++ j {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			} {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			} if(list[i].equals(list[j])) {
				flag++;
				break;
				} list[i].equals(list[j]) list[i].equals list[i] list i list[j] list j {
				flag++;
				break;
				} flag++ flag break; if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		} flag != 0 flag 0 {
			System.out.println("No");
		} System.out.println("No") System.out.println System.out System System.out "No" {
			System.out.println("Yes");
		} System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	}

} public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	}

} Main
import java.util.Scanner;

public class Main{

	public static void main(String[] args) {

		Scanner scanner = new Scanner(System.in);
		//n
		String temp = scanner.nextLine();
		int n = Integer.parseInt(temp);
		//しりとり
		int flag = 0;
		String[] list = new String[n];
		for(int i = 0; i < n; i++) {
			list[i] = scanner.nextLine();
			if(i != 0) {
				if(list[i].charAt(0) != list[i - 1].charAt(list[i - 1].length() - 1)) {
					flag++;
					break;
				}
			}
			for(int j = 0; j < i; j++) {
				if(list[i].equals(list[j])) {
				flag++;
				break;
				}
			}
		}
		if(flag != 0) {
			System.out.println("No");
		}else {
			System.out.println("Yes");
		}
	}

}