import java.util.Scanner;


public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
} import java.util.Scanner; Scanner java.util public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
} Main public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String[] w = new String[n]; w new String[n] n String ans; ans for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			w[i] = sc.next();
		} {
			w[i] = sc.next();
		} w[i] = sc.next() w[i] w i sc.next() sc.next sc for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		} {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		} for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			} int j = i+1; int j = i+1; j i+1 i 1 j < n j n j++ j++ j {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			} {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			} if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				} w[i].equals(w[j]) w[i].equals w[i] w i w[j] w j {
					System.out.println("No");
					return;
				} System.out.println("No") System.out.println System.out System System.out "No" return; for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		} {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		} if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			} w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0) w[i-1].charAt(w[i-1].length()-1) w[i-1].charAt w[i-1] w i-1 i 1 w[i-1].length()-1 w[i-1].length() w[i-1].length w[i-1] w i-1 i 1 1 w[i].charAt(0) w[i].charAt w[i] w i 0 {
				System.out.println("No");
				return;
			} System.out.println("No") System.out.println System.out System System.out "No" return; 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 sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
} public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
} Main
import java.util.Scanner;


public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		String[] w = new String[n];
		String ans;
		for(int i = 0; i < n; i++) {
			w[i] = sc.next();
		}
		for(int i = 0; i < n; i++) {
			for(int j = i+1; j < n; j++) {
				if(w[i].equals(w[j])) {
					System.out.println("No");
					return;
				}
			}
		}
		for(int i = 1; i < n; i++) {
			if(w[i-1].charAt(w[i-1].length()-1)!=w[i].charAt(0)) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
}
