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 s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	}

} 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 s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	}

} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		String s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	} main {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		String s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc String s = "Yes"; s "Yes" Set<String> set = new HashSet<>(); set new HashSet<>() String w = sc.next(); w sc.next() sc.next sc set.add(w) set.add set w char e = w.charAt(w.length()-1); e w.charAt(w.length()-1) w.charAt w w.length()-1 w.length() w.length w 1 for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		} int i=0; int i=0; i 0 i<N-1 i N-1 N 1 i++ i++ i {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		} {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		} w = sc.next() w sc.next() sc.next sc if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      } set.add(w) && e==w.charAt(0) set.add(w) set.add set w e==w.charAt(0) e w.charAt(0) w.charAt w 0 {
				e = w.charAt(w.length()-1);
		        set.add(w);
		     } e = w.charAt(w.length()-1) e w.charAt(w.length()-1) w.charAt w w.length()-1 w.length() w.length w 1 set.add(w) set.add set w {
		        s = "No";
		      } s = "No" s "No" sc.close() sc.close sc System.out.println(s) System.out.println System.out System System.out s String[] args args public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		String s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	}

} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int N = sc.nextInt();
		String s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	}

} 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 s = "Yes";
		Set<String> set = new HashSet<>();
		String w = sc.next();
		set.add(w);
		char e = w.charAt(w.length()-1);

		for(int i=0; i<N-1; i++) {
			w = sc.next();
			if(set.add(w) && e==w.charAt(0)){
				e = w.charAt(w.length()-1);
		        set.add(w);
		     }else{
		        s = "No";
		      }
		}
		sc.close();
		System.out.println(s);
	}

}