import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
      String s[] = new String[n];
     int flag1 = 0;
     int flag2 = 0;
      
      for(int i =0;i<n;i++){
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      }
		Arrays.sort(s);
      
      for(int i =1;i<n;i++){
        if(s[i-1].equals(s[i])){flag2=1;}
      }
      if(flag1==0&&flag2==0){System.out.print("Yes");}
      else{System.out.print("No");}
      
    }
} import java.util.*; util.* java class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
      String s[] = new String[n];
     int flag1 = 0;
     int flag2 = 0;
      
      for(int i =0;i<n;i++){
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      }
		Arrays.sort(s);
      
      for(int i =1;i<n;i++){
        if(s[i-1].equals(s[i])){flag2=1;}
      }
      if(flag1==0&&flag2==0){System.out.print("Yes");}
      else{System.out.print("No");}
      
    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
      String s[] = new String[n];
     int flag1 = 0;
     int flag2 = 0;
      
      for(int i =0;i<n;i++){
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      }
		Arrays.sort(s);
      
      for(int i =1;i<n;i++){
        if(s[i-1].equals(s[i])){flag2=1;}
      }
      if(flag1==0&&flag2==0){System.out.print("Yes");}
      else{System.out.print("No");}
      
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
      String s[] = new String[n];
     int flag1 = 0;
     int flag2 = 0;
      
      for(int i =0;i<n;i++){
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      }
		Arrays.sort(s);
      
      for(int i =1;i<n;i++){
        if(s[i-1].equals(s[i])){flag2=1;}
      }
      if(flag1==0&&flag2==0){System.out.print("Yes");}
      else{System.out.print("No");}
      
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String s[] = new String[n]; s new String[n] n int flag1 = 0; flag1 0 int flag2 = 0; flag2 0 for(int i =0;i<n;i++){
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      } int i =0; int i =0; i 0 i<n i n i++ i++ i {
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      } {
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      } s[i]  = sc.next() s[i] s i sc.next() sc.next sc if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }} i>0 i 0 {
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }} if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        } s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0) s[i-1].charAt(s[i-1].length()-1) s[i-1].charAt s[i-1] s i-1 i 1 s[i-1].length()-1 s[i-1].length() s[i-1].length s[i-1] s i-1 i 1 1 s[i].charAt(0) s[i].charAt s[i] s i 0 {
          flag1=1;
        } flag1=1 flag1 1 Arrays.sort(s) Arrays.sort Arrays s for(int i =1;i<n;i++){
        if(s[i-1].equals(s[i])){flag2=1;}
      } int i =1; int i =1; i 1 i<n i n i++ i++ i {
        if(s[i-1].equals(s[i])){flag2=1;}
      } {
        if(s[i-1].equals(s[i])){flag2=1;}
      } if(s[i-1].equals(s[i])){flag2=1;} s[i-1].equals(s[i]) s[i-1].equals s[i-1] s i-1 i 1 s[i] s i {flag2=1;} flag2=1 flag2 1 if(flag1==0&&flag2==0){System.out.print("Yes");}
      else{System.out.print("No");} flag1==0&&flag2==0 flag1==0 flag1 0 flag2==0 flag2 0 {System.out.print("Yes");} System.out.print("Yes") System.out.print System.out System System.out "Yes" {System.out.print("No");} System.out.print("No") System.out.print System.out System System.out "No" String[] args args
import java.util.*;

class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
      String s[] = new String[n];
     int flag1 = 0;
     int flag2 = 0;
      
      for(int i =0;i<n;i++){
        s[i]  = sc.next();
      if(i>0){
        if(s[i-1].charAt(s[i-1].length()-1)!=s[i].charAt(0)){
          flag1=1;
        }}
      }
		Arrays.sort(s);
      
      for(int i =1;i<n;i++){
        if(s[i-1].equals(s[i])){flag2=1;}
      }
      if(flag1==0&&flag2==0){System.out.print("Yes");}
      else{System.out.print("No");}
      
    }
}