import java.util.*;
public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	}
} import java.util.*; util.* java public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	} main {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String data[] = new String[n]; data new String[n] n for (int i = 0;i<n ;i++ ) {
			data[i] = sc.next();
		} int i = 0; int i = 0; i 0 i<n i n i++ i++ i {
			data[i] = sc.next();
		} {
			data[i] = sc.next();
		} data[i] = sc.next() data[i] data i sc.next() sc.next sc for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		} int i = 0; int i = 0; i 0 i<n i n i++ i++ i {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		} {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		} for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			} int j = i+1; int j = i+1; j i+1 i 1 j<n j n j++ j++ j {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			} {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			} if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				} data[i].equals(data[j]) data[i].equals data[i] data i data[j] data j {
					System.out.println("No");
					System.exit(0);
				} System.out.println("No") System.out.println System.out System System.out "No" System.exit(0) System.exit System 0 for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		} int i = 0; int i = 0; i 0 i<n-1 i n-1 n 1 i++ i++ i {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		} {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		} if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			} data[i].charAt(data[i].length()-1)==data[i+1].charAt(0) data[i].charAt(data[i].length()-1) data[i].charAt data[i] data i data[i].length()-1 data[i].length() data[i].length data[i] data i 1 data[i+1].charAt(0) data[i+1].charAt data[i+1] data i+1 i 1 0 {

			} {
				System.out.println("No");
				System.exit(0);
			} System.out.println("No") System.out.println System.out System System.out "No" System.exit(0) System.exit System 0 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 sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	}
} public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	}
} Main
import java.util.*;
public class Main{
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String data[] = new String[n];

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

		for (int i = 0;i<n ;i++ ) {
			for (int j = i+1;j<n ;j++ ) {
				if (data[i].equals(data[j])) {
					System.out.println("No");
					System.exit(0);
				}
			}
		}

		for (int i = 0;i<n-1 ;i++ ) {
			if (data[i].charAt(data[i].length()-1)==data[i+1].charAt(0)) {

			}else{
				System.out.println("No");
				System.exit(0);
			}
		}
		System.out.println("Yes");

	}
}
