import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		System.out.println("Yes");
	}
} import java.util.*; util.* java public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		System.out.println("Yes");
	}
} Main public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		System.out.println("Yes");
	} main {
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		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 ArrayList<String> words = new ArrayList<String>(); words new ArrayList<String>() for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		} int i=0; int i=0; i 0 i<N i N i++ i++ i {
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		} {
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		} String w = sc.next(); w sc.next() sc.next sc if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			} i !=0 i 0 {
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			} String lastword = words.get(i-1); lastword words.get(i-1) words.get words i-1 i 1 int wordcnt = lastword.length(); wordcnt lastword.length() lastword.length lastword Character initial = w.charAt(0); initial w.charAt(0) w.charAt w 0 if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				} words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1))) words.indexOf(w) != -1 words.indexOf(w) words.indexOf words w -1 1 !(initial.equals(lastword.charAt(wordcnt-1))) (initial.equals(lastword.charAt(wordcnt-1))) initial.equals initial lastword.charAt(wordcnt-1) lastword.charAt lastword wordcnt-1 wordcnt 1 {
				System.out.println("No");
				return;
				} System.out.println("No") System.out.println System.out System System.out "No" return; words.add(w) words.add words w 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);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		System.out.println("Yes");
	}
} public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		System.out.println("Yes");
	}
} Main
import java.util.*;
public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);
		// 整数の入力
		int N = sc.nextInt();
		ArrayList<String> words = new ArrayList<String>();
		for(int i=0;i<N;i++){
			String w = sc.next();
			if(i !=0 ){
				String lastword = words.get(i-1);
				int wordcnt = lastword.length(); 
				Character initial = w.charAt(0);
				if(words.indexOf(w) != -1 || !(initial.equals(lastword.charAt(wordcnt-1)))){
				System.out.println("No");
				return;
				}
			}
			words.add(w);
		}
		System.out.println("Yes");
	}
}