import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

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

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

		sc.close();
	}

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

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

		sc.close();
	}

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

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

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

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

		sc.close();
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String word1 = sc.next(); word1 sc.next() sc.next sc String ans = "Yes"; ans "Yes" Set<String> set = new HashSet<>(); set new HashSet<>() set.add(word1) set.add set word1 char tale = word1.charAt(word1.length() - 1); tale word1.charAt(word1.length() - 1) word1.charAt word1 word1.length() - 1 word1.length() word1.length word1 1 for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		} int i = 0; int i = 0; i 0 i < n - 1 i n - 1 n 1 i++ i++ i {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		} {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		} String str = sc.next(); str sc.next() sc.next sc if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			} set.contains(str) || str.charAt(0) != tale set.contains(str) set.contains set str str.charAt(0) != tale str.charAt(0) str.charAt str 0 tale {
				ans = "No";
				break;
			} ans = "No" ans "No" break; set.add(str) set.add set str tale = str.charAt(str.length() - 1) tale str.charAt(str.length() - 1) str.charAt str str.length() - 1 str.length() str.length str 1 System.out.println(ans) System.out.println System.out System System.out ans sc.close() sc.close sc String[] args args public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

		sc.close();
	}

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

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

		sc.close();
	}

} Main
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

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

		int n = sc.nextInt();
		String word1 = sc.next();
		String ans = "Yes";
		Set<String> set = new HashSet<>();
		set.add(word1);
		char tale = word1.charAt(word1.length() - 1);

		for (int i = 0; i < n - 1; i++) {
			String str = sc.next();
			if (set.contains(str) || str.charAt(0) != tale) {
				ans = "No";
				break;
			}
			set.add(str);
			tale = str.charAt(str.length() - 1);
		}

		System.out.println(ans);

		sc.close();
	}

}
