import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	}
} import java.util.ArrayList; ArrayList java.util import java.util.Scanner; Scanner java.util public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	}
} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	} main {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int n = scan.nextInt(); n scan.nextInt() scan.nextInt scan ArrayList<String> arr = new ArrayList<>(); arr new ArrayList<>() String start = null; start null String end = null; end null String judge = "Yes"; judge "Yes" for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		} {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		} String w = scan.next(); w scan.next() scan.next scan if (arr.contains(w)) {
				judge = "No";
				break;
			} arr.contains(w) arr.contains arr w {
				judge = "No";
				break;
			} judge = "No" judge "No" break; start = w.substring(0, 1) start w.substring(0, 1) w.substring w 0 1 if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			} end != null && !start.equals(end) end != null end null !start.equals(end) start.equals(end) start.equals start end {
				judge = "No";
				break;
			} judge = "No" judge "No" break; arr.add(w) arr.add arr w end = w.substring(w.length()-1) end w.substring(w.length()-1) w.substring w w.length()-1 w.length() w.length w 1 System.out.println(judge) System.out.println System.out System System.out judge scan.close() scan.close scan String[] args args public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	}
} Main
import java.util.ArrayList;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		int n = scan.nextInt();
		ArrayList<String> arr = new ArrayList<>();
		String start = null;
		String end = null;
		String judge = "Yes";
		
		for(int i = 0; i < n ; i++) {
			String w = scan.next();
			if (arr.contains(w)) {
				judge = "No";
				break;
			}
			
			start = w.substring(0, 1);
			if(end != null && !start.equals(end)) {
				judge = "No";
				break;
			}
			arr.add(w);
			end = w.substring(w.length()-1);
		}
		System.out.println(judge);
		scan.close();
	}
}