import java.util.*;
public class Main {

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

} import java.util.*; util.* java public class Main {

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

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

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

} public class Main {

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

} Main
import java.util.*;
public class Main {

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

}
