
import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} import java.util.HashMap; HashMap java.util import java.util.Map; Map java.util import java.util.Scanner; Scanner java.util public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} Main static Scanner scanner; scanner public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	} main {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	} scanner = new Scanner(System.in) scanner new Scanner(System.in) int N=gi(); N gi() gi Map<String, Integer> m=new HashMap<String, Integer>(); m new HashMap<String, Integer>() String b=gs(); b gs() gs m.put(b, 1) m.put m b 1 for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        } int i=1; int i=1; i 1 i<N i N i++ i++ i {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        } {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        } String w=gs(); w gs() gs if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	} m.containsKey(w) m.containsKey m w {
        		System.out.println("No");
        		return;
        	} System.out.println("No") System.out.println System.out System System.out "No" return; if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	} b.charAt(b.length()-1)!=w.charAt(0) b.charAt(b.length()-1) b.charAt b b.length()-1 b.length() b.length b 1 w.charAt(0) w.charAt w 0 {
        		System.out.println("No");
        		return;
        	} System.out.println("No") System.out.println System.out System System.out "No" return; m.put(w,1) m.put m w 1 b=w b w System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	} d {
		String a=String.valueOf(n);
		return (long)a.length();
	} String a=String.valueOf(n); a String.valueOf(n) String.valueOf String n return (long)a.length(); (long)a.length() a.length a long n n // 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	} gs {
		return scanner.next();
	} return scanner.next(); scanner.next() scanner.next scanner // intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	} gi {
		return Integer.parseInt(scanner.next());
	} return Integer.parseInt(scanner.next()); Integer.parseInt(scanner.next()) Integer.parseInt Integer scanner.next() scanner.next scanner // longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	} gl {
		return Long.parseLong(scanner.next());
	} return Long.parseLong(scanner.next()); Long.parseLong(scanner.next()) Long.parseLong Long scanner.next() scanner.next scanner // doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	} gd {
		return Double.parseDouble(scanner.next());
	} return Double.parseDouble(scanner.next()); Double.parseDouble(scanner.next()) Double.parseDouble Double scanner.next() scanner.next scanner public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
} Main

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class Main {

	static Scanner scanner;

	public static void main(String[] args) {
	    scanner = new Scanner(System.in);

        int N=gi();
        Map<String, Integer> m=new HashMap<String, Integer>();
        String b=gs();
        m.put(b, 1);
        for (int i=1; i<N; i++) {
        	String w=gs();
        	if (m.containsKey(w)) {
        		System.out.println("No");
        		return;
        	}
        	if (b.charAt(b.length()-1)!=w.charAt(0)) {
        		System.out.println("No");
        		return;
        	}
          m.put(w,1);
        	b=w;
        }


        System.out.println("Yes");
//        if (a>0) {
//        	System.out.println("Yes");
//        }else {
//        	System.out.println("No");
//        }
	}


	public static long d(long n) {
		String a=String.valueOf(n);
		return (long)a.length();
	}

	// 文字列として入力を取得
	public static String gs() {
		return scanner.next();
	}

	// intとして入力を取得
	public static int gi() {
		return Integer.parseInt(scanner.next());
	}

	// longとして入力を取得
	public static long gl() {
		return Long.parseLong(scanner.next());
	}

	// doubleとして入力を取得
	public static double gd() {
		return Double.parseDouble(scanner.next());
	}
}