import java.io.*;
import java.util.*;


public class Main {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	}

	static String INPUT = null;

	private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
} import java.io.*; io.* java import java.util.*; util.* java public class Main {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	}

	static String INPUT = null;

	private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
} Main private static Scanner sc; sc private static Printer pr; pr static String INPUT = null; INPUT null private static void solve() {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	} solve {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	} int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc Set<String> hs = new HashSet<>(); hs new HashSet<>() String[] w = new String[n]; w new String[n] n for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		} {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		} w[i] = sc.next() w[i] w i sc.next() sc.next sc if (hs.contains(w[i])) {
				pr.println("No");
				return;
			} hs.contains(w[i]) hs.contains hs w[i] w i {
				pr.println("No");
				return;
			} pr.println("No") pr.println pr "No" return; hs.add(w[i]) hs.add hs w[i] w i for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		} int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		} {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		} if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			} w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0) w[i - 1].charAt(w[i - 1].length() - 1) w[i - 1].charAt w[i - 1] w i - 1 i 1 w[i - 1].length() - 1 w[i - 1].length() w[i - 1].length w[i - 1] w i - 1 i 1 1 w[i].charAt(0) w[i].charAt w[i] w i 0 {
				pr.println("No");
				return;
			} pr.println("No") pr.println pr "No" return; pr.println("Yes") pr.println pr "Yes" // ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	} main {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	} sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes())) sc new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes())) pr = new Printer(System.out) pr new Printer(System.out) solve() solve pr.flush() pr.flush pr String[] args args private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	} Printer Printer(OutputStream out) {
			super(out);
		} Printer {
			super(out);
		} super(out) super out OutputStream out out PrintWriter public class Main {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	}

	static String INPUT = null;

	private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
} public class Main {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	}

	static String INPUT = null;

	private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
} Main
import java.io.*;
import java.util.*;


public class Main {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		Set<String> hs = new HashSet<>();
		String[] w = new String[n];
		for (int i = 0; i < n; i++) {
			w[i] = sc.next();
			
			if (hs.contains(w[i])) {
				pr.println("No");
				return;
			}

			hs.add(w[i]);
		}
		
		for (int i = 1; i < n; i++) {
			if (w[i - 1].charAt(w[i - 1].length() - 1) != w[i].charAt(0)) {
				pr.println("No");
				return;
			}
		}

		pr.println("Yes");
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(INPUT == null ? System.in : new ByteArrayInputStream(INPUT.getBytes()));
		pr = new Printer(System.out);

		solve();

//		pr.close();
		pr.flush();
//		sc.close();
	}

	static String INPUT = null;

	private static class Printer extends PrintWriter {
		Printer(OutputStream out) {
			super(out);
		}
	}
}
