import java.util.Scanner;

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

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