import java.util.*;

class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<String> list = new ArrayList<String>();
		int i = 0;
		String hoge = sc.next();
		list.add(hoge);
		for(i = 1; i < n; i++){
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		}
		System.out.print(i == n?"Yes":"No");
	}
} import java.util.*; util.* java class Main{
	public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<String> list = new ArrayList<String>();
		int i = 0;
		String hoge = sc.next();
		list.add(hoge);
		for(i = 1; i < n; i++){
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		}
		System.out.print(i == n?"Yes":"No");
	}
} Main public static void main(String args[]){
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<String> list = new ArrayList<String>();
		int i = 0;
		String hoge = sc.next();
		list.add(hoge);
		for(i = 1; i < n; i++){
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		}
		System.out.print(i == n?"Yes":"No");
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		ArrayList<String> list = new ArrayList<String>();
		int i = 0;
		String hoge = sc.next();
		list.add(hoge);
		for(i = 1; i < n; i++){
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		}
		System.out.print(i == n?"Yes":"No");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc ArrayList<String> list = new ArrayList<String>(); list new ArrayList<String>() int i = 0; i 0 String hoge = sc.next(); hoge sc.next() sc.next sc list.add(hoge) list.add list hoge for(i = 1; i < n; i++){
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		} i = 1; i = 1 i 1 i < n i n i++ i++ i {
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		} {
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		} String w = sc.next(); w sc.next() sc.next sc hoge = hoge.substring(hoge.length()-1,hoge.length()) hoge hoge.substring(hoge.length()-1,hoge.length()) hoge.substring hoge hoge.length()-1 hoge.length() hoge.length hoge 1 hoge.length() hoge.length hoge String hoge2 = w.substring(0,1); hoge2 w.substring(0,1) w.substring w 0 1 if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			} !hoge.equals(hoge2) hoge.equals(hoge2) hoge.equals hoge hoge2 {
				break;
			} break; if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			} list.indexOf(w) > -1 list.indexOf(w) list.indexOf list w -1 1 {
				break;
			} break; {
				list.add(w);
				hoge = w;
			} list.add(w) list.add list w hoge = w hoge w System.out.print(i == n?"Yes":"No") System.out.print System.out System System.out i == n?"Yes":"No" i == n i n "Yes" "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();
		ArrayList<String> list = new ArrayList<String>();
		int i = 0;
		String hoge = sc.next();
		list.add(hoge);
		for(i = 1; i < n; i++){
			String w = sc.next();
			hoge = hoge.substring(hoge.length()-1,hoge.length());
			String hoge2 = w.substring(0,1);
			if(!hoge.equals(hoge2)){
				break;
			}else if(list.indexOf(w) > -1){
				break;
			}else{
				list.add(w);
				hoge = w;
			}
		}
		System.out.print(i == n?"Yes":"No");
	}
}
