import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Set;

public class Main {
	public static void main(String[] args) {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	}

	static int gcd(int a, int b) {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
} import java.io.IOException; IOException java.io import java.util.Arrays; Arrays java.util import java.util.HashSet; HashSet java.util import java.util.InputMismatchException; InputMismatchException java.util import java.util.Set; Set java.util public class Main {
	public static void main(String[] args) {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	}

	static int gcd(int a, int b) {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
} Main public static void main(String[] args) {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	} main {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	} FasterScanner sc = new FasterScanner(); sc new FasterScanner() int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc char c = ' '; c ' ' Set<String> s = new HashSet<String>(); s new HashSet<String>() for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		} {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		} String str = sc.nextString(); str sc.nextString() sc.nextString sc if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			} !s.add(str) s.add(str) s.add s str {
				System.out.println("No");
				return;
			} System.out.println("No") System.out.println System.out System System.out "No" return; {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			} if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				} i > 0 && str.charAt(0) != c i > 0 i 0 str.charAt(0) != c str.charAt(0) str.charAt str 0 c {
					System.out.println("No");
					return;
				} System.out.println("No") System.out.println System.out System System.out "No" return; c = str.charAt(str.length() - 1) c str.charAt(str.length() - 1) str.charAt str str.length() - 1 str.length() str.length str 1 System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args static int gcd(int a, int b) {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	} gcd {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	} int temp; temp while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		} b != 0 b 0 {
			temp = a % b;

			a = b;
			b = temp;
		} temp = a % b temp a % b a b a = b a b b = temp b temp return a; a int a a int b b public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	} FasterScanner private byte[] buf = new byte[1024]; buf new byte[1024] 1024 private int curChar; curChar private int numChars; numChars public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		} read {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		} if (numChars == -1)
				throw new InputMismatchException(); numChars == -1 numChars -1 1 throw new InputMismatchException(); new InputMismatchException() if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			} curChar >= numChars curChar numChars {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			} curChar = 0 curChar 0 try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				} catch (IOException e) {
					throw new InputMismatchException();
				} IOException e {
					throw new InputMismatchException();
				} throw new InputMismatchException(); new InputMismatchException() {
					numChars = System.in.read(buf);
				} numChars = System.in.read(buf) numChars System.in.read(buf) System.in.read System.in System System.in buf if (numChars <= 0)
					return -1; numChars <= 0 numChars 0 return -1; -1 1 return buf[curChar++]; buf[curChar++] buf curChar++ curChar public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		} nextLine {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		} int c = read(); c read() read while (isSpaceChar(c))
				c = read(); isSpaceChar(c) isSpaceChar c c = read() c read() read StringBuilder res = new StringBuilder(); res new StringBuilder() do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c)); !isEndOfLine(c) isEndOfLine(c) isEndOfLine c {
				res.appendCodePoint(c);
				c = read();
			} res.appendCodePoint(c) res.appendCodePoint res c c = read() c read() read return res.toString(); res.toString() res.toString res public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		} nextString {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		} int c = read(); c read() read while (isSpaceChar(c))
				c = read(); isSpaceChar(c) isSpaceChar c c = read() c read() read StringBuilder res = new StringBuilder(); res new StringBuilder() do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c)); !isSpaceChar(c) isSpaceChar(c) isSpaceChar c {
				res.appendCodePoint(c);
				c = read();
			} res.appendCodePoint(c) res.appendCodePoint res c c = read() c read() read return res.toString(); res.toString() res.toString res public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		} nextLong {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		} int c = read(); c read() read while (isSpaceChar(c))
				c = read(); isSpaceChar(c) isSpaceChar c c = read() c read() read int sgn = 1; sgn 1 if (c == '-') {
				sgn = -1;
				c = read();
			} c == '-' c '-' {
				sgn = -1;
				c = read();
			} sgn = -1 sgn -1 1 c = read() c read() read long res = 0; res 0 do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c)); !isSpaceChar(c) isSpaceChar(c) isSpaceChar c {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} if (c < '0' || c > '9')
					throw new InputMismatchException(); c < '0' || c > '9' c < '0' c '0' c > '9' c '9' throw new InputMismatchException(); new InputMismatchException() res *= 10 res 10 res += c - '0' res c - '0' c '0' c = read() c read() read return res * sgn; res * sgn res sgn public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		} nextInt {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		} int c = read(); c read() read while (isSpaceChar(c))
				c = read(); isSpaceChar(c) isSpaceChar c c = read() c read() read int sgn = 1; sgn 1 if (c == '-') {
				sgn = -1;
				c = read();
			} c == '-' c '-' {
				sgn = -1;
				c = read();
			} sgn = -1 sgn -1 1 c = read() c read() read int res = 0; res 0 do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c)); !isSpaceChar(c) isSpaceChar(c) isSpaceChar c {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} if (c < '0' || c > '9')
					throw new InputMismatchException(); c < '0' || c > '9' c < '0' c '0' c > '9' c '9' throw new InputMismatchException(); new InputMismatchException() res *= 10 res 10 res += c - '0' res c - '0' c '0' c = read() c read() read return res * sgn; res * sgn res sgn public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		} nextIntArray {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		} int[] arr = new int[n]; arr new int[n] n for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				arr[i] = nextInt();
			} {
				arr[i] = nextInt();
			} arr[i] = nextInt() arr[i] arr i nextInt() nextInt return arr; arr int n n public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		} nextIntArray {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		} int[] arr = new int[n + offset]; arr new int[n + offset] n + offset n offset for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				arr[i + offset] = nextInt();
			} {
				arr[i + offset] = nextInt();
			} arr[i + offset] = nextInt() arr[i + offset] arr i + offset i offset nextInt() nextInt return arr; arr int n n int offset offset public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		} nextLongArray {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		} long[] arr = new long[n]; arr new long[n] n for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				arr[i] = nextLong();
			} {
				arr[i] = nextLong();
			} arr[i] = nextLong() arr[i] arr i nextLong() nextLong return arr; arr int n n public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		} nextLongArray {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		} long[] arr = new long[n + offset]; arr new long[n + offset] n + offset n offset for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			} int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
				arr[i + offset] = nextLong();
			} {
				arr[i + offset] = nextLong();
			} arr[i + offset] = nextLong() arr[i + offset] arr i + offset i offset nextLong() nextLong return arr; arr int n n int offset offset private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		} isSpaceChar {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		} return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1; c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == '\t' c == '\r' c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1 c == ' ' c ' ' c == '\n' c '\n' c == '\r' c '\r' c == '\t' c '\t' c == -1 c -1 1 int c c private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		} isEndOfLine {
			return c == '\n' || c == '\r' || c == -1;
		} return c == '\n' || c == '\r' || c == -1; c == '\n' || c == '\r' || c == -1 c == '\n' || c == '\r' || c == -1 c == '\n' c '\n' c == '\r' c '\r' c == -1 c -1 1 int c c public class Main {
	public static void main(String[] args) {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	}

	static int gcd(int a, int b) {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
} public class Main {
	public static void main(String[] args) {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	}

	static int gcd(int a, int b) {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
} Main
import java.io.IOException;
import java.util.Arrays;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.Set;

public class Main {
	public static void main(String[] args) {
		FasterScanner sc = new FasterScanner();

		int n = sc.nextInt();
		char c = ' ';
		Set<String> s = new HashSet<String>();
		for (int i = 0; i < n; i++) {
			String str = sc.nextString();
			if (!s.add(str)) {
				System.out.println("No");
				return;
			} else {
				if (i > 0 && str.charAt(0) != c) {
					System.out.println("No");
					return;
				}
			}
			c = str.charAt(str.length() - 1);
		}
		System.out.println("Yes");

	}

	static int gcd(int a, int b) {
		int temp;
		while (b != 0) {
			temp = a % b;

			a = b;
			b = temp;
		}
		return a;
	}

	public static class FasterScanner {
		private byte[] buf = new byte[1024];
		private int curChar;
		private int numChars;

		public int read() {
			if (numChars == -1)
				throw new InputMismatchException();
			if (curChar >= numChars) {
				curChar = 0;
				try {
					numChars = System.in.read(buf);
				} catch (IOException e) {
					throw new InputMismatchException();
				}
				if (numChars <= 0)
					return -1;
			}
			return buf[curChar++];
		}

		public String nextLine() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isEndOfLine(c));
			return res.toString();
		}

		public String nextString() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			StringBuilder res = new StringBuilder();
			do {
				res.appendCodePoint(c);
				c = read();
			} while (!isSpaceChar(c));
			return res.toString();
		}

		public long nextLong() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			long res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int nextInt() {
			int c = read();
			while (isSpaceChar(c))
				c = read();
			int sgn = 1;
			if (c == '-') {
				sgn = -1;
				c = read();
			}
			int res = 0;
			do {
				if (c < '0' || c > '9')
					throw new InputMismatchException();
				res *= 10;
				res += c - '0';
				c = read();
			} while (!isSpaceChar(c));
			return res * sgn;
		}

		public int[] nextIntArray(int n) {
			int[] arr = new int[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextInt();
			}
			return arr;
		}

		public int[] nextIntArray(int n, int offset) {
			int[] arr = new int[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextInt();
			}
			return arr;
		}

		public long[] nextLongArray(int n) {
			long[] arr = new long[n];
			for (int i = 0; i < n; i++) {
				arr[i] = nextLong();
			}
			return arr;
		}

		public long[] nextLongArray(int n, int offset) {
			long[] arr = new long[n + offset];
			for (int i = 0; i < n; i++) {
				arr[i + offset] = nextLong();
			}
			return arr;
		}

		private boolean isSpaceChar(int c) {
			return c == ' ' || c == '\n' || c == '\r' || c == '\t' || c == -1;
		}

		private boolean isEndOfLine(int c) {
			return c == '\n' || c == '\r' || c == -1;
		}
	}
}