import java.util.Scanner;

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

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