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