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


public class Main {

    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    }


    private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    }
}
class Point {
    private int left;
    private int right;

    public int getLeft() {
        return left;
    }

    public int getRight() {
        return right;
    }
    public Point(int left,int right) {
        this.left = left;
        this.right = right;
    }
}

class InputReader extends BufferedReader {
    StringTokenizer tokenizer;

    public InputReader(InputStream inputStream) {
        super(new InputStreamReader(inputStream), 32768);
    }

    public InputReader(String filename) {
        super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
        return tokenizer.nextToken();
    }

    public Integer nextInt() {
        return Integer.valueOf(next());
    }
    public Long nextLong() {return  Long.valueOf(next());}

    static class OutputWriter extends PrintWriter {
        public OutputWriter(OutputStream outputStream) {
            super(outputStream);
        }

        public OutputWriter(Writer writer) {
            super(writer);
        }

        public OutputWriter(String filename) throws FileNotFoundException {
            super(filename);
        }

        public void close() {
            super.close();
        }
    }
} import java.io.*; io.* java import java.util.*; util.* java public class Main {

    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    }


    private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    }
} Main public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out InputReader in = new InputReader(inputStream); in new InputReader(inputStream) InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream); out new InputReader.OutputWriter(outputStream) int n = in.nextInt(); n in.nextInt() in.nextInt in HashSet<String> set = new HashSet<>(); set new HashSet<>() boolean first = false; first false char firstLetter = ' '; firstLetter ' ' char lastLetter = ' '; lastLetter ' ' while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        } n-->0 n-- n 0 {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        } String s = in.next(); s in.next() in.next in if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            } !first first {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            } lastLetter = s.charAt(s.length() - 1) lastLetter s.charAt(s.length() - 1) s.charAt s s.length() - 1 s.length() s.length s 1 first = true first true {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            } firstLetter = s.charAt(0) firstLetter s.charAt(0) s.charAt s 0 if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                } firstLetter!=lastLetter firstLetter lastLetter {
                    out.println("No");
                    out.flush();
                    return;
                } out.println("No") out.println out "No" out.flush() out.flush out return; lastLetter = s.charAt(s.length() - 1) lastLetter s.charAt(s.length() - 1) s.charAt s s.length() - 1 s.length() s.length s 1 if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            } set.contains(s) set.contains set s {
                out.println("No");
                out.flush();
                return;
            } out.println("No") out.println out "No" out.flush() out.flush out return; set.add(s) set.add set s out.println("Yes") out.println out "Yes" out.flush() out.flush out String[] args args private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    } mergeTwoArrays {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    } int [] res = new int[a.length + b.length]; res new int[a.length + b.length] a.length + b.length a.length a a.length b.length b b.length int i = 0; i 0 int j = 0; j 0 int index = 0; index 0 while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        } i<a.length && j<b.length i<a.length i a.length a a.length j<b.length j b.length b b.length {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        } if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            } a[i]<b[j] a[i] a i b[j] b j {
                res[index++] = a[i++];
            } res[index++] = a[i++] res[index++] res index++ index a[i++] a i++ i {
                res[index++] = b[j++];
            } res[index++] = b[j++] res[index++] res index++ index b[j++] b j++ j System.out.println(i + " " + j) System.out.println System.out System System.out i + " " + j i + " " + j i " " j if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        } j == b.length - 1 j b.length - 1 b.length b b.length 1 {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        } while (i<a.length) {
                res[index++] = a[i++];
            } i<a.length i a.length a a.length {
                res[index++] = a[i++];
            } res[index++] = a[i++] res[index++] res index++ index a[i++] a i++ i {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        } while (j<b.length) {
                res[index++] = b[j++];
            } j<b.length j b.length b b.length {
                res[index++] = b[j++];
            } res[index++] = b[j++] res[index++] res index++ index b[j++] b j++ j return res; res int [] a a int [] b b class Point {
    private int left;
    private int right;

    public int getLeft() {
        return left;
    }

    public int getRight() {
        return right;
    }
    public Point(int left,int right) {
        this.left = left;
        this.right = right;
    }
} Point private int left; left private int right; right public int getLeft() {
        return left;
    } getLeft {
        return left;
    } return left; left public int getRight() {
        return right;
    } getRight {
        return right;
    } return right; right public Point(int left,int right) {
        this.left = left;
        this.right = right;
    } Point {
        this.left = left;
        this.right = right;
    } this.left = left this.left this this.left left this.right = right this.right this this.right right int left left int right right class InputReader extends BufferedReader {
    StringTokenizer tokenizer;

    public InputReader(InputStream inputStream) {
        super(new InputStreamReader(inputStream), 32768);
    }

    public InputReader(String filename) {
        super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
        return tokenizer.nextToken();
    }

    public Integer nextInt() {
        return Integer.valueOf(next());
    }
    public Long nextLong() {return  Long.valueOf(next());}

    static class OutputWriter extends PrintWriter {
        public OutputWriter(OutputStream outputStream) {
            super(outputStream);
        }

        public OutputWriter(Writer writer) {
            super(writer);
        }

        public OutputWriter(String filename) throws FileNotFoundException {
            super(filename);
        }

        public void close() {
            super.close();
        }
    }
} InputReader StringTokenizer tokenizer; tokenizer public InputReader(InputStream inputStream) {
        super(new InputStreamReader(inputStream), 32768);
    } InputReader {
        super(new InputStreamReader(inputStream), 32768);
    } super(new InputStreamReader(inputStream), 32768) super new InputStreamReader(inputStream) 32768 InputStream inputStream inputStream public InputReader(String filename) {
        super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
    } InputReader {
        super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
    } super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename))) super new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)) String filename filename public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
        return tokenizer.nextToken();
    } next {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
        return tokenizer.nextToken();
    } while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        } tokenizer == null || !tokenizer.hasMoreTokens() tokenizer == null tokenizer null !tokenizer.hasMoreTokens() tokenizer.hasMoreTokens() tokenizer.hasMoreTokens tokenizer {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        } try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            } catch (IOException e) {
                throw new RuntimeException();
            } IOException e {
                throw new RuntimeException();
            } throw new RuntimeException(); new RuntimeException() {
                tokenizer = new StringTokenizer(readLine());
            } tokenizer = new StringTokenizer(readLine()) tokenizer new StringTokenizer(readLine()) return tokenizer.nextToken(); tokenizer.nextToken() tokenizer.nextToken tokenizer public Integer nextInt() {
        return Integer.valueOf(next());
    } nextInt {
        return Integer.valueOf(next());
    } return Integer.valueOf(next()); Integer.valueOf(next()) Integer.valueOf Integer next() next public Long nextLong() {return  Long.valueOf(next());} nextLong {return  Long.valueOf(next());} return  Long.valueOf(next()); Long.valueOf(next()) Long.valueOf Long next() next static class OutputWriter extends PrintWriter {
        public OutputWriter(OutputStream outputStream) {
            super(outputStream);
        }

        public OutputWriter(Writer writer) {
            super(writer);
        }

        public OutputWriter(String filename) throws FileNotFoundException {
            super(filename);
        }

        public void close() {
            super.close();
        }
    } OutputWriter public OutputWriter(OutputStream outputStream) {
            super(outputStream);
        } OutputWriter {
            super(outputStream);
        } super(outputStream) super outputStream OutputStream outputStream outputStream public OutputWriter(Writer writer) {
            super(writer);
        } OutputWriter {
            super(writer);
        } super(writer) super writer Writer writer writer public OutputWriter(String filename) throws FileNotFoundException {
            super(filename);
        } OutputWriter {
            super(filename);
        } super(filename) super filename String filename filename public void close() {
            super.close();
        } close {
            super.close();
        } super.close() super.close super PrintWriter BufferedReader public class Main {

    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    }


    private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    }
} public class Main {

    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    }


    private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    }
} Main
import java.io.*;
import java.util.*;


public class Main {

    public static void main(String[] args) throws IOException {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        InputReader in = new InputReader(inputStream);
        InputReader.OutputWriter out = new InputReader.OutputWriter(outputStream);

        int n = in.nextInt();
        HashSet<String> set = new HashSet<>();
        boolean first = false;
        char firstLetter = ' ';
        char lastLetter = ' ';
        while (n-->0) {
            String s = in.next();
            if(!first) {
                lastLetter = s.charAt(s.length() - 1);
                first = true;
            }
            else {
                firstLetter = s.charAt(0);
                if(firstLetter!=lastLetter) {
                    out.println("No");
                    out.flush();
                    return;
                }
                lastLetter = s.charAt(s.length() - 1);
            }
            if(set.contains(s)) {
                out.println("No");
                out.flush();
                return;
            }
            set.add(s);

        }

        out.println("Yes");
        out.flush();
    }


    private static int [] mergeTwoArrays(int [] a, int [] b) {
        int [] res = new int[a.length + b.length];
        int i = 0;
        int j = 0;
        int index = 0;
        while (i<a.length && j<b.length) {
            if(a[i]<b[j]) {
                res[index++] = a[i++];
            }
            else {
                res[index++] = b[j++];
            }
        }
        System.out.println(i + " " + j);
        if(j == b.length - 1) {
            while (i<a.length) {
                res[index++] = a[i++];
            }
        }
        else {
            while (j<b.length) {
                res[index++] = b[j++];
            }
        }
        return res;
    }
}
class Point {
    private int left;
    private int right;

    public int getLeft() {
        return left;
    }

    public int getRight() {
        return right;
    }
    public Point(int left,int right) {
        this.left = left;
        this.right = right;
    }
}

class InputReader extends BufferedReader {
    StringTokenizer tokenizer;

    public InputReader(InputStream inputStream) {
        super(new InputStreamReader(inputStream), 32768);
    }

    public InputReader(String filename) {
        super(new InputStreamReader(Thread.currentThread().getContextClassLoader().getResourceAsStream(filename)));
    }

    public String next() {
        while (tokenizer == null || !tokenizer.hasMoreTokens()) {
            try {
                tokenizer = new StringTokenizer(readLine());
            } catch (IOException e) {
                throw new RuntimeException();
            }
        }
        return tokenizer.nextToken();
    }

    public Integer nextInt() {
        return Integer.valueOf(next());
    }
    public Long nextLong() {return  Long.valueOf(next());}

    static class OutputWriter extends PrintWriter {
        public OutputWriter(OutputStream outputStream) {
            super(outputStream);
        }

        public OutputWriter(Writer writer) {
            super(writer);
        }

        public OutputWriter(String filename) throws FileNotFoundException {
            super(filename);
        }

        public void close() {
            super.close();
        }
    }
}