import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.Reader;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.NoSuchElementException;
import java.io.InputStreamReader;
import java.io.InputStream;
 
/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    
    static class TaskB {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        }
 
    }
    
    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        }
        public double nextDouble() { 
        	return Double.parseDouble(next());
        }
    }
    
    
    
}


  import java.io.OutputStream; OutputStream java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.PrintWriter; PrintWriter java.io import java.util.Arrays; Arrays java.util import java.io.IOException; IOException java.io import java.io.BufferedReader; BufferedReader java.io import java.io.Reader; Reader java.io import java.util.Comparator; Comparator java.util import java.util.HashMap; HashMap java.util import java.util.Map; Map java.util import java.util.NoSuchElementException; NoSuchElementException java.util import java.io.InputStreamReader; InputStreamReader java.io import java.io.InputStream; InputStream java.io public class Main {
    public static void main(String[] args) {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    
    static class TaskB {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        }
 
    }
    
    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        }
        public double nextDouble() { 
        	return Double.parseDouble(next());
        }
    }
    
    
    
} Main public static void main(String[] args) {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    } main {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    } OutputStream outputStream = System.out; outputStream System.out System System.out FastScanner in = new FastScanner(); in new FastScanner() PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) TaskB solver = new TaskB(); solver new TaskB() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class TaskB {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        }
 
    } TaskB public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        } solve {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        } Integer a = in.nextInt(); a in.nextInt() in.nextInt in String[] str = new String[a]; str new String[a] a for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	} int n=0; int n=0; n 0 n < a n a n++ n++ n {
        		str[n] = in.next();
        	} {
        		str[n] = in.next();
        	} str[n] = in.next() str[n] str n in.next() in.next in Map<String, Integer> m = new HashMap<String, Integer>(); m new HashMap<String, Integer>() boolean flag = true; flag true for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	} int f=0; int f=0; f 0 f<a f a f++ f++ f {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	} {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	} int v; v if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    } m.containsKey(str[f]) m.containsKey m str[f] str f {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } flag = false flag false break; {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    } if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	} f != 0 f 0 {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	} if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		} !str[f].startsWith(str[f-1].substring(str[f-1].length()-1)) str[f].startsWith(str[f-1].substring(str[f-1].length()-1)) str[f].startsWith str[f] str f str[f-1].substring(str[f-1].length()-1) str[f-1].substring str[f-1] str f-1 f 1 str[f-1].length()-1 str[f-1].length() str[f-1].length str[f-1] str f-1 f 1 1 {
        	    			
        	    			flag = false;
        	    			break;
        	    		} flag = false flag false break; v = 1 v 1 m.put(str[f], v) m.put m str[f] str f v if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	} flag {
        		out.print("Yes"); 
        	} out.print("Yes") out.print out "Yes" {
        		out.print("No");
        	} out.print("No") out.print out "No" int testNumber testNumber FastScanner in in PrintWriter out out static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        }
        public double nextDouble() { 
        	return Double.parseDouble(next());
        }
    } FastScanner private final InputStream in = System.in; in System.in System System.in private final byte[] buffer = new byte[1024]; buffer new byte[1024] 1024 private int ptr = 0; ptr 0 private int buflen = 0; buflen 0 private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        } hasNextByte {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        } if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            } ptr < buflen ptr buflen {
                return true;
            } return true; true {
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            } ptr = 0 ptr 0 try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                } IOException e {
                    e.printStackTrace();
                } e.printStackTrace() e.printStackTrace e {
                    buflen = in.read(buffer);
                } buflen = in.read(buffer) buflen in.read(buffer) in.read in buffer if (buflen <= 0) {
                    return false;
                } buflen <= 0 buflen 0 {
                    return false;
                } return false; false return true; true private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;} readByte { if (hasNextByte()) return buffer[ptr++]; else return -1;} if (hasNextByte()) return buffer[ptr++]; else return -1; hasNextByte() hasNextByte return buffer[ptr++]; buffer[ptr++] buffer ptr++ ptr return -1; -1 1 private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;} isPrintableChar { return 33 <= c && c <= 126;} return 33 <= c && c <= 126; 33 <= c && c <= 126 33 <= c 33 c c <= 126 c 126 int c c public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} hasNext { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();} while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; hasNextByte() && !isPrintableChar(buffer[ptr]) hasNextByte() hasNextByte !isPrintableChar(buffer[ptr]) isPrintableChar(buffer[ptr]) isPrintableChar buffer[ptr] buffer ptr ptr++ ptr return hasNextByte(); hasNextByte() hasNextByte public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        } next {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() StringBuilder sb = new StringBuilder(); sb new StringBuilder() int b = readByte(); b readByte() readByte while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            } isPrintableChar(b) isPrintableChar b {
                sb.appendCodePoint(b);
                b = readByte();
            } sb.appendCodePoint(b) sb.appendCodePoint sb b b = readByte() b readByte() readByte return sb.toString(); sb.toString() sb.toString sb public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        } nextLong {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        } if (!hasNext()) throw new NoSuchElementException(); !hasNext() hasNext() hasNext throw new NoSuchElementException(); new NoSuchElementException() long n = 0; n 0 boolean minus = false; minus false int b = readByte(); b readByte() readByte if (b == '-') {
                minus = true;
                b = readByte();
            } b == '-' b '-' {
                minus = true;
                b = readByte();
            } minus = true minus true b = readByte() b readByte() readByte if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            } b < '0' || '9' < b b < '0' b '0' '9' < b '9' b {
                throw new NumberFormatException();
            } throw new NumberFormatException(); new NumberFormatException() while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            } true {
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            } if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                } '0' <= b && b <= '9' '0' <= b '0' b b <= '9' b '9' {
                    n *= 10;
                    n += b - '0';
                } n *= 10 n 10 n += b - '0' n b - '0' b '0' if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                } b == -1 || !isPrintableChar(b) b == -1 b -1 1 !isPrintableChar(b) isPrintableChar(b) isPrintableChar b {
                    return minus ? -n : n;
                } return minus ? -n : n; minus ? -n : n minus -n n n {
                    throw new NumberFormatException();
                } throw new NumberFormatException(); new NumberFormatException() b = readByte() b readByte() readByte public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        } nextInt {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        } long nl = nextLong(); nl nextLong() nextLong if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException(); nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE nl < Integer.MIN_VALUE nl Integer.MIN_VALUE Integer Integer.MIN_VALUE nl > Integer.MAX_VALUE nl Integer.MAX_VALUE Integer Integer.MAX_VALUE throw new NumberFormatException(); new NumberFormatException() return (int) nl; (int) nl public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        } nextIntArray {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        } final int[] res = new int[n]; res new int[n] n for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                res[i] = nextInt();
            } {
                res[i] = nextInt();
            } res[i] = nextInt() res[i] res i nextInt() nextInt return res; res final int n n public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        } nextIntArray2D {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        } final int[][] res = new int[n][]; res new int[n][] n for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                res[i] = nextIntArray(k);
            } {
                res[i] = nextIntArray(k);
            } res[i] = nextIntArray(k) res[i] res i nextIntArray(k) nextIntArray k return res; res final int n n final int k k public double nextDouble() { 
        	return Double.parseDouble(next());
        } nextDouble { 
        	return Double.parseDouble(next());
        } return Double.parseDouble(next()); Double.parseDouble(next()) Double.parseDouble Double next() next public class Main {
    public static void main(String[] args) {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    
    static class TaskB {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        }
 
    }
    
    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        }
        public double nextDouble() { 
        	return Double.parseDouble(next());
        }
    }
    
    
    
} public class Main {
    public static void main(String[] args) {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    
    static class TaskB {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        }
 
    }
    
    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        }
        public double nextDouble() { 
        	return Double.parseDouble(next());
        }
    }
    
    
    
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.Arrays;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.Reader;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Map;
import java.util.NoSuchElementException;
import java.io.InputStreamReader;
import java.io.InputStream;
 
/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 */
public class Main {
    public static void main(String[] args) {
        OutputStream outputStream = System.out;
        FastScanner in = new FastScanner();
        PrintWriter out = new PrintWriter(outputStream);
        TaskB solver = new TaskB();
        solver.solve(1, in, out);
        out.close();
    }
    
    static class TaskB {
        public void solve(int testNumber, FastScanner in, PrintWriter out) {
        	
        	Integer a = in.nextInt(); 
        	String[] str = new String[a];
        	for (int n=0; n < a; n++) {
        		str[n] = in.next();
        	}
        	
        	Map<String, Integer> m = new HashMap<String, Integer>();
        	boolean flag = true;
        	for (int f=0; f<a; f++) {
        	    int v;
        	    if (m.containsKey(str[f])) {
        	        // Mapに登録済み
        	    	
        	    	flag = false;
        	    	break;
        	    } else {
        	        // Mapに未登録
        	    	if (f != 0) {
        	    		if (!str[f].startsWith(str[f-1].substring(str[f-1].length()-1))) {
        	    			
        	    			flag = false;
        	    			break;
        	    		}
        	    	}
        	        v = 1;
        	        m.put(str[f], v);
        	    }
        	   
        	}
        	if (flag) {
        		out.print("Yes"); 
        	} else {
        		out.print("No");
        	}
        	

        	
        }
 
    }
    
    static class FastScanner {
        private final InputStream in = System.in;
        private final byte[] buffer = new byte[1024];
        private int ptr = 0;
        private int buflen = 0;
        private boolean hasNextByte() {
            if (ptr < buflen) {
                return true;
            }else{
                ptr = 0;
                try {
                    buflen = in.read(buffer);
                } catch (IOException e) {
                    e.printStackTrace();
                }
                if (buflen <= 0) {
                    return false;
                }
            }
            return true;
        }
        private int readByte() { if (hasNextByte()) return buffer[ptr++]; else return -1;}
        private static boolean isPrintableChar(int c) { return 33 <= c && c <= 126;}
        public boolean hasNext() { while(hasNextByte() && !isPrintableChar(buffer[ptr])) ptr++; return hasNextByte();}
        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            StringBuilder sb = new StringBuilder();
            int b = readByte();
            while(isPrintableChar(b)) {
                sb.appendCodePoint(b);
                b = readByte();
            }
            return sb.toString();
        }
        public long nextLong() {
            if (!hasNext()) throw new NoSuchElementException();
            long n = 0;
            boolean minus = false;
            int b = readByte();
            if (b == '-') {
                minus = true;
                b = readByte();
            }
            if (b < '0' || '9' < b) {
                throw new NumberFormatException();
            }
            while(true){
                if ('0' <= b && b <= '9') {
                    n *= 10;
                    n += b - '0';
                }else if(b == -1 || !isPrintableChar(b)){
                    return minus ? -n : n;
                }else{
                    throw new NumberFormatException();
                }
                b = readByte();
            }
        }
        public int nextInt() {
            long nl = nextLong();
            if (nl < Integer.MIN_VALUE || nl > Integer.MAX_VALUE) throw new NumberFormatException();
            return (int) nl;
        }
        public int[] nextIntArray(final int n) {
            final int[] res = new int[n];
            for (int i = 0; i < n; i++) {
                res[i] = nextInt();
            }
            return res;
        }
        public int[][] nextIntArray2D(final int n, final int k) {
            final int[][] res = new int[n][];
            for (int i = 0; i < n; i++) {
                res[i] = nextIntArray(k);
            }
            return res;
        }
        public double nextDouble() { 
        	return Double.parseDouble(next());
        }
    }
    
    
    
}


 
