import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    }
    
} import java.io.BufferedReader; BufferedReader java.io import java.io.InputStreamReader; InputStreamReader java.io import java.util.*; util.* java public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    }
    
} Main public static void main(String[] args) {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    } main {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    } Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in))); in new Scanner(new BufferedReader(new InputStreamReader(System.in))) int n = in.nextInt(); n in.nextInt() in.nextInt in String [] array = new String[n]; array new String[n] n for (int i = 0; i < n; i++) array[i] = in.next(); int i = 0; int i = 0; i 0 i < n i n i++ i++ i array[i] = in.next(); array[i] = in.next() array[i] array i in.next() in.next in List<String> list = new ArrayList<>(); list new ArrayList<>() list.add(array[0]) list.add list array[0] array 0 char c = array[0].charAt(array[0].length()-1); c array[0].charAt(array[0].length()-1) array[0].charAt array[0] array 0 array[0].length()-1 array[0].length() array[0].length array[0] array 0 1 for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        } int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        } {
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        } if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            } list.contains(array[i]) || array[i].charAt(0) != c list.contains(array[i]) list.contains list array[i] array i array[i].charAt(0) != c array[i].charAt(0) array[i].charAt array[i] array i 0 c {
                System.out.println("No");
                return;
            } System.out.println("No") System.out.println System.out System System.out "No" return; c = array[i].charAt(array[i].length()-1) c array[i].charAt(array[i].length()-1) array[i].charAt array[i] array i array[i].length()-1 array[i].length() array[i].length array[i] array i 1 list.add(array[i]) list.add list array[i] array i 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) {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    }
    
} public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    }
    
} Main
import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.util.*;

public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(new BufferedReader(new InputStreamReader(System.in)));
        int n = in.nextInt();
        String [] array = new String[n];
        for (int i = 0; i < n; i++) array[i] = in.next();
        List<String> list = new ArrayList<>();
        list.add(array[0]);
        char c = array[0].charAt(array[0].length()-1);
        for (int i = 1; i < n; i++){
            if (list.contains(array[i]) || array[i].charAt(0) != c){
                System.out.println("No");
                return;
            }
            c = array[i].charAt(array[i].length()-1);
            list.add(array[i]);
        }
        System.out.println("Yes");
    }
    
}