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

public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		int num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	}
} 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 num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	}
} Main public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		int num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	} main {
		Scanner scan = new Scanner(System.in);
		
		int num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	} Scanner scan = new Scanner(System.in); scan new Scanner(System.in) int num = scan.nextInt(); num scan.nextInt() scan.nextInt scan ArrayList<String>  str = new ArrayList<String>(); str new ArrayList<String>() for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		} int i = 0 ; int i = 0 ; i 0 i < num i num i++ i++ i {
			str.add(scan.next());
		} {
			str.add(scan.next());
		} str.add(scan.next()) str.add str scan.next() scan.next scan for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		} int j = 1 ; int j = 1 ; j 1 j < str.size() j str.size() str.size str j++ j++ j {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		} {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		} if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			} str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0) str.get(j - 1).charAt(str.get(j - 1).length() - 1) str.get(j - 1).charAt str.get(j - 1) str.get str j - 1 j 1 str.get(j - 1).length() - 1 str.get(j - 1).length() str.get(j - 1).length str.get(j - 1) str.get str j - 1 j 1 1 str.get(j).charAt(0) str.get(j).charAt str.get(j) str.get str j 0 {
				System.out.print("No");
				return;
			} System.out.print("No") System.out.print System.out System System.out "No" return; String target = str.get(j); target str.get(j) str.get str j for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			} int k = 0 ; int k = 0 ; k 0 k < str.size() k str.size() str.size str k++ k++ k {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			} {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			} if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				} j != k j k {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				} if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					} target.equals(str.get(k)) target.equals target str.get(k) str.get str k {
						System.out.print("No");
						return;
					} System.out.print("No") System.out.print System.out System System.out "No" return; scan.close() scan.close scan System.out.print("Yes") System.out.print System.out System System.out "Yes" String[] args args public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		int num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	}
} public class Main {
	public static void main(String[] args) {
		Scanner scan = new Scanner(System.in);
		
		int num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	}
} 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 num = scan.nextInt();
		
		ArrayList<String>  str = new ArrayList<String>();
		for(int i = 0 ; i < num ; i++) {
			str.add(scan.next());
		}
		
		for(int j = 1 ; j < str.size() ; j++) {
			if(str.get(j - 1).charAt(str.get(j - 1).length() - 1) != str.get(j).charAt(0)) {
				System.out.print("No");
				return;
			}
			
			String target = str.get(j);
			for(int k = 0 ; k < str.size() ; k++) {
				if(j != k) {
					if(target.equals(str.get(k))) {
						System.out.print("No");
						return;
					}
				}
			}
		}
		
		scan.close();
		
		System.out.print("Yes");
	}
}
