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());
        }
    }
    
    
    
}


 


Measured memory_bytes: 23380