import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		String ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		}


		System.out.println(ans);
		sc.close();
	}

} import java.util.ArrayList; ArrayList java.util import java.util.List; List java.util 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 ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.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 ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		}


		System.out.println(ans);
		sc.close();
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		String ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.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 ans = "Yes"; ans "Yes" List<String> list = new ArrayList<>(); list new ArrayList<>() sc.nextLine() sc.nextLine sc String word = sc.nextLine(); word sc.nextLine() sc.nextLine sc list.add(word) list.add list word String strfin = word.substring(word.length()-1); strfin word.substring(word.length()-1) word.substring word word.length()-1 word.length() word.length word 1 for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		} int i = 0; int i = 0; i 0 i < N-1 i N-1 N 1 i++ i++ i {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		} {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		} word = sc.nextLine() word sc.nextLine() sc.nextLine sc if(ans.equals("No")) {
				continue;
			} ans.equals("No") ans.equals ans "No" {
				continue;
			} continue; if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			} !(word.substring(0,1).equals(strfin)) (word.substring(0,1).equals(strfin)) word.substring(0,1).equals word.substring(0,1) word.substring word 0 1 strfin {
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			} ans = "No" ans "No" for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			} int j = 0; int j = 0; j 0 j <= i j i j++ j++ j {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			} {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			} if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				} word.equals(list.get(j)) word.equals word list.get(j) list.get list j {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				} ans = "No" ans "No" list.add(word) list.add list word strfin = word.substring(word.length()-1) strfin word.substring(word.length()-1) word.substring word word.length()-1 word.length() word.length word 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 ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.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 ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		}


		System.out.println(ans);
		sc.close();
	}

} Main
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();

		String ans = "Yes";
		List<String> list = new ArrayList<>();
		sc.nextLine();
		String word = sc.nextLine();

		list.add(word);
		String strfin = word.substring(word.length()-1);

		for(int i = 0; i < N-1; i++) {
			word = sc.nextLine();

			if(ans.equals("No")) {
				continue;
			}
			if(!(word.substring(0,1).equals(strfin))){
				ans = "No";
				//System.out.println(word + " " + word.substring(0,1) +"　"+ strfin);
			}

			for(int j = 0; j <= i; j++) {
				if(word.equals(list.get(j))) {
					ans = "No";
					//System.out.println(word + " "+ list.get(j));
				}
			}
			list.add(word);
			strfin = word.substring(word.length()-1);
		}


		System.out.println(ans);
		sc.close();
	}

}