import java.util.*;

public class Main {

	public static void main(
			String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	}
} import java.util.*; util.* java public class Main {

	public static void main(
			String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	}
} Main public static void main(
			String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	} main {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	} Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc boolean result = true; result true String w = sc.next(); w sc.next() sc.next sc ArrayList wList = new ArrayList(); wList new ArrayList() wList.add(w) wList.add wList w char s = w.charAt(w.length() - 1); s w.charAt(w.length() - 1) w.charAt w w.length() - 1 w.length() w.length w 1 for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		} {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		} w = sc.next() w sc.next() sc.next sc if (wList.contains(w)) {
				result = false;
				break;
			} wList.contains(w) wList.contains wList w {
				result = false;
				break;
			} result = false result false break; wList.add(w) wList.add wList w if (s != w.charAt(0)) {
				result = false;
				break;
			} s != w.charAt(0) s w.charAt(0) w.charAt w 0 {
				result = false;
				break;
			} result = false result false break; s = w.charAt(w.length() - 1) s w.charAt(w.length() - 1) w.charAt w w.length() - 1 w.length() w.length w 1 System.out.println(result ? "Yes" : "No") System.out.println System.out System System.out result ? "Yes" : "No" result "Yes" "No" String[] args args public class Main {

	public static void main(
			String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	}
} public class Main {

	public static void main(
			String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	}
} Main
import java.util.*;

public class Main {

	public static void main(
			String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		boolean result = true;
		String w = sc.next();
		ArrayList wList = new ArrayList();
		wList.add(w);
		char s = w.charAt(w.length() - 1);
		for (int i = 1; i < n; i++) {
			w = sc.next();
			if (wList.contains(w)) {
				result = false;
				break;
			}
			wList.add(w);
			if (s != w.charAt(0)) {
				result = false;
				break;
			}
			s = w.charAt(w.length() - 1);
		}
		System.out.println(result ? "Yes" : "No");
	}
}
