import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		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 in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		if (flag > 0)
			System.out.println("No");
		else
			System.out.println("Yes");
		

	}

} Main public static void main(String[] args) {
		
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		if (flag > 0)
			System.out.println("No");
		else
			System.out.println("Yes");
		

	} main {
		
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		if (flag > 0)
			System.out.println("No");
		else
			System.out.println("Yes");
		

	} Scanner in = new Scanner(System.in); in new Scanner(System.in) int n = in.nextInt(); n in.nextInt() in.nextInt in String[] w = new String[n]; w new String[n] n for (int i = 0; i < n; i++)
			w[i] = in.next(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i w[i] = in.next(); w[i] = in.next() w[i] w i in.next() in.next in int flag = 0; flag 0 for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		} int i = 0; int i = 0; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		} {
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		} if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++; w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0) w[i].charAt(w[i].length() - 1) w[i].charAt w[i] w i w[i].length() - 1 w[i].length() w[i].length w[i] w i 1 w[i + 1].charAt(0) w[i + 1].charAt w[i + 1] w i + 1 i 1 0 flag++ flag for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			} int j = i + 1; int j = i + 1; j i + 1 i 1 j < n j n j++ j++ j {
				if (w[i].equals(w[j]))
					flag++;
			} {
				if (w[i].equals(w[j]))
					flag++;
			} if (w[i].equals(w[j]))
					flag++; w[i].equals(w[j]) w[i].equals w[i] w i w[j] w j flag++ flag if (flag > 0)
			System.out.println("No");
		else
			System.out.println("Yes"); flag > 0 flag 0 System.out.println("No") System.out.println System.out System System.out "No" 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 in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		if (flag > 0)
			System.out.println("No");
		else
			System.out.println("Yes");
		

	}

} public class Main {

	public static void main(String[] args) {
		
		Scanner in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		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 in = new Scanner(System.in);
		int n = in.nextInt();
		String[] w = new String[n];
		for (int i = 0; i < n; i++)
			w[i] = in.next();
		int flag = 0;
		
		for (int i = 0; i < n - 1; i++){
			if (w[i].charAt(w[i].length() - 1) != w[i + 1].charAt(0))
				flag++;
			for (int j = i + 1; j < n; j++){
				if (w[i].equals(w[j]))
					flag++;
			}
		}
		
		if (flag > 0)
			System.out.println("No");
		else
			System.out.println("Yes");
		

	}

}