import java.util.*;


public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        System.out.println("Yes");
        
	}
} import java.util.*; util.* java public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        System.out.println("Yes");
        
	}
} Main public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        System.out.println("Yes");
        
	} main {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        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 String[] w = new String[n]; w new String[n] n w[0] = sc.next() w[0] w 0 sc.next() sc.next sc String ans = "No"; ans "No" for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        } int i=1; int i=1; i 1 i<n i n i++ i++ i {
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        } {
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        } w[i] = sc.next() w[i] w i sc.next() sc.next sc for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            } int j=0; int j=0; j 0 j<i j i j++ j++ j {
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            } {
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            } if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                } w[i].equals(w[j]) w[i].equals w[i] w i w[j] w j {
                    System.out.println(ans);
                    return;
                } System.out.println(ans) System.out.println System.out System System.out ans return; if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            } w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1) w[i].charAt(0) w[i].charAt w[i] w i 0 w[i-1].charAt(w[i-1].length()-1) w[i-1].charAt w[i-1] w i-1 i 1 w[i-1].length()-1 w[i-1].length() w[i-1].length w[i-1] w i-1 i 1 1 {
                System.out.println(ans);
                return;
            } System.out.println(ans) System.out.println System.out System System.out ans return; 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) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        System.out.println("Yes");
        
	}
} public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        System.out.println("Yes");
        
	}
} Main
import java.util.*;


public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int n= sc.nextInt();
        String[] w = new String[n];
        w[0] = sc.next();
        String ans = "No";
        
        for(int i=1; i<n; i++){
            w[i] = sc.next();
            for(int j=0; j<i; j++){
                if(w[i].equals(w[j])){
                    System.out.println(ans);
                    return;
                }
            }
            if(w[i].charAt(0)!=w[i-1].charAt(w[i-1].length()-1)){
                System.out.println(ans);
                return;
            }
        }
        
        System.out.println("Yes");
        
	}
}