import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc= new Scanner(System.in);
		int n=sc.nextInt();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
} import java.util.LinkedHashMap; LinkedHashMap java.util import java.util.Map; Map java.util 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();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				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();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	} main {
		Scanner sc= new Scanner(System.in);
		int n=sc.nextInt();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				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 Map<String,Integer> words = new LinkedHashMap<>(); words new LinkedHashMap<>() char[] ini=new char[n]; ini new char[n] n char[] end =new char[n]; end new char[n] n for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		} int i=0; int i=0; i 0 i<n i n i++ i++ i {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		} {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		} String s=sc.next(); s sc.next() sc.next sc if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			} words.get(s)!=null words.get(s) words.get words s null {
				System.out.println("No");
				return;
			} System.out.println("No") System.out.println System.out System System.out "No" return; {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			} words.put(s,1) words.put words s 1 ini[i]=s.charAt(0) ini[i] ini i s.charAt(0) s.charAt s 0 end[i]=s.charAt(s.length()-1) end[i] end i s.charAt(s.length()-1) s.charAt s s.length()-1 s.length() s.length s 1 for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		} int i=0; int i=0; i 0 i<n-1 i n-1 n 1 i++ i++ i {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		} {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		} if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			} end[i]!=ini[i+1] end[i] end i ini[i+1] ini i+1 i 1 {
				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();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				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();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
} Main
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc= new Scanner(System.in);
		int n=sc.nextInt();
		Map<String,Integer> words = new LinkedHashMap<>();
		char[] ini=new char[n];
		char[] end =new char[n];

		for(int i=0; i<n; i++) {
			String s=sc.next();
			if(words.get(s)!=null) {
				System.out.println("No");
				return;
			}else {
				words.put(s,1);
				ini[i]=s.charAt(0);
				end[i]=s.charAt(s.length()-1);
			}
		}

		for(int i=0;i<n-1;i++) {
			if(end[i]!=ini[i+1]) {
				System.out.println("No");
				return;
			}
		}
		System.out.println("Yes");
	}
}