
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}
} import java.util.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util import java.util.Set; Set java.util public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}
} Main public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	} main {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	} new Main().solveB() new Main().solveB new Main() String[] args args private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} solveA {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} Scanner scanner = null; scanner null int numA = 0; numA 0 int numB = 0; numB 0 try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		} {
			if (scanner != null) {
				scanner.close();
			}
		} if (scanner != null) {
				scanner.close();
			} scanner != null scanner null {
				scanner.close();
			} scanner.close() scanner.close scanner {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} scanner = new Scanner(System.in) scanner new Scanner(System.in) numA = scanner.nextInt() numA scanner.nextInt() scanner.nextInt scanner numB = scanner.nextInt() numB scanner.nextInt() scanner.nextInt scanner for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			} int i = 1; int i = 1; i 1 i < 4 i 4 i++ i++ i {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			} {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			} if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				} numA * numB * i % 2 != 0 numA * numB * i % 2 numA * numB * i numA * numB * i numA numB i 2 0 {
					System.out.println("Yes");
					return;
				} System.out.println("Yes") System.out.println System.out System System.out "Yes" return; System.out.println("No") System.out.println System.out System System.out "No" private void solveB() {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} solveB {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} Scanner scanner = null; scanner null int numN = 0; numN 0 try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		} {
			if (scanner != null) {
				scanner.close();
			}
		} if (scanner != null) {
				scanner.close();
			} scanner != null scanner null {
				scanner.close();
			} scanner.close() scanner.close scanner {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} scanner = new Scanner(System.in) scanner new Scanner(System.in) numN = scanner.nextInt() numN scanner.nextInt() scanner.nextInt scanner String[] wk = new String[numN]; wk new String[numN] numN Set<String> wkSet = new HashSet<String>(); wkSet new HashSet<String>() for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			} int i = 0; int i = 0; i 0 i < wk.length i wk.length wk wk.length i++ i++ i {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			} {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			} String wkI = scanner.next(); wkI scanner.next() scanner.next scanner wk[i] = wkI wk[i] wk i wkI if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				} wkSet.contains(wk[i]) wkSet.contains wkSet wk[i] wk i {
					System.out.println("No");
					return;
				} System.out.println("No") System.out.println System.out System System.out "No" return; wkSet.add(wk[i]) wkSet.add wkSet wk[i] wk i if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				} i != 0 i 0 {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				} String wkIm1 = wk[i - 1]; wkIm1 wk[i - 1] wk i - 1 i 1 if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					} wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0) wkIm1.charAt(wkIm1.length()-1) wkIm1.charAt wkIm1 wkIm1.length()-1 wkIm1.length() wkIm1.length wkIm1 1 wkI.charAt(0) wkI.charAt wkI 0 {
						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" private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} solveC {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} Scanner scanner = null; scanner null int numN = 0; numN 0 int numK = 0; numK 0 int numS = 0; numS 0 try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		} {
			if (scanner != null) {
				scanner.close();
			}
		} if (scanner != null) {
				scanner.close();
			} scanner != null scanner null {
				scanner.close();
			} scanner.close() scanner.close scanner {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} scanner = new Scanner(System.in) scanner new Scanner(System.in) numN = scanner.nextInt() numN scanner.nextInt() scanner.nextInt scanner System.out.println("") System.out.println System.out System System.out "" private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} solveD {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	} Scanner scanner = null; scanner null int numN = 0; numN 0 int numK = 0; numK 0 int numS = 0; numS 0 try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		} {
			if (scanner != null) {
				scanner.close();
			}
		} if (scanner != null) {
				scanner.close();
			} scanner != null scanner null {
				scanner.close();
			} scanner.close() scanner.close scanner {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} scanner = new Scanner(System.in) scanner new Scanner(System.in) numN = scanner.nextInt() numN scanner.nextInt() scanner.nextInt scanner System.out.println("") System.out.println System.out System System.out "" public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}
} public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}
} Main

import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

public class Main {

	public static void main(String[] args) {
		//		new Main().solveA();
		new Main().solveB();
		// new Main().solveC();
		// new Main().solveD();
	}

	private void solveA() {
		Scanner scanner = null;
		int numA = 0;
		int numB = 0;

		try {
			scanner = new Scanner(System.in);
			numA = scanner.nextInt();
			numB = scanner.nextInt();
			for (int i = 1; i < 4; i++) {
				if (numA * numB * i % 2 != 0) {
					System.out.println("Yes");
					return;
				}
			}

			System.out.println("No");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveB() {
		Scanner scanner = null;
		int numN = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();
			String[] wk = new String[numN];

			Set<String> wkSet = new HashSet<String>();
			for (int i = 0; i < wk.length; i++) {
				String wkI = scanner.next();
				wk[i] = wkI;
				if (wkSet.contains(wk[i])) {
					System.out.println("No");
					return;
				}
				wkSet.add(wk[i]);
				if (i != 0) {
					String wkIm1 = wk[i - 1];
					if(wkIm1.charAt(wkIm1.length()-1)!=wkI.charAt(0)) {
						System.out.println("No");
						return;
					}

				}
			}

			System.out.println("Yes");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveC() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}

	private void solveD() {
		Scanner scanner = null;
		int numN = 0;
		int numK = 0;
		int numS = 0;

		try {
			scanner = new Scanner(System.in);
			numN = scanner.nextInt();

			System.out.println("");

		} finally {
			if (scanner != null) {
				scanner.close();
			}
		}
	}
}