import java.util.*;

class Main{
	public static void main(String args[]){
      Scanner scan = new Scanner(System.in);
      int N = scan.nextInt();
      
      String previous = scan.next();
      String next;
      Set<String> used_words = new HashSet<String>();
      used_words.add(previous);
      
      while(N>1){
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      }//while
      scan.close();
      System.out.println("Yes");
      
    }
} import java.util.*; util.* java class Main{
	public static void main(String args[]){
      Scanner scan = new Scanner(System.in);
      int N = scan.nextInt();
      
      String previous = scan.next();
      String next;
      Set<String> used_words = new HashSet<String>();
      used_words.add(previous);
      
      while(N>1){
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      }//while
      scan.close();
      System.out.println("Yes");
      
    }
} Main public static void main(String args[]){
      Scanner scan = new Scanner(System.in);
      int N = scan.nextInt();
      
      String previous = scan.next();
      String next;
      Set<String> used_words = new HashSet<String>();
      used_words.add(previous);
      
      while(N>1){
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      }//while
      scan.close();
      System.out.println("Yes");
      
    } main {
      Scanner scan = new Scanner(System.in);
      int N = scan.nextInt();
      
      String previous = scan.next();
      String next;
      Set<String> used_words = new HashSet<String>();
      used_words.add(previous);
      
      while(N>1){
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      }//while
      scan.close();
      System.out.println("Yes");
      
    } Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int N = scan.nextInt(); N scan.nextInt() scan.nextInt scan String previous = scan.next(); previous scan.next() scan.next scan String next; next Set<String> used_words = new HashSet<String>(); used_words new HashSet<String>() used_words.add(previous) used_words.add used_words previous while(N>1){
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      }//while N>1 N 1 {
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      } next = scan.next() next scan.next() scan.next scan if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        } !((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next)) ((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next)) (previous.charAt(previous.length()-1)==next.charAt(0)) previous.charAt(previous.length()-1) previous.charAt previous previous.length()-1 previous.length() previous.length previous 1 next.charAt(0) next.charAt next 0 used_words.add(next) used_words.add used_words next {
          System.out.println("No");
          scan.close();
          return;
        } System.out.println("No") System.out.println System.out System System.out "No" scan.close() scan.close scan return; previous = next previous next N-- N scan.close() scan.close scan System.out.println("Yes") System.out.println System.out System System.out "Yes" String args[] args
import java.util.*;

class Main{
	public static void main(String args[]){
      Scanner scan = new Scanner(System.in);
      int N = scan.nextInt();
      
      String previous = scan.next();
      String next;
      Set<String> used_words = new HashSet<String>();
      used_words.add(previous);
      
      while(N>1){
        next = scan.next();
        if(!((previous.charAt(previous.length()-1)==next.charAt(0))&&used_words.add(next))){
          System.out.println("No");
          scan.close();
          return;
        }
        previous = next;
        N--;
      }//while
      scan.close();
      System.out.println("Yes");
      
    }
}