
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        try (PrintWriter out = new PrintWriter(System.out); Scanner sc = new Scanner(System.in);) {
            Task task = new Task();
            task.solve(sc, out);
            out.flush();

        } catch (Exception e) {
            // DO NOT USE
        }
    }

    static class Task {
        public void solve(Scanner sc, PrintWriter out) {
            // TODO
            int a = nint(sc);

            List<String> list = new ArrayList<>();
            String w1 = nstr(sc);
            list.add(w1);
            String[] ww = w1.split("");

            String stock = ww[ww.length-1];

            boolean flag = true;
            String w = "";
            for (int i = 0; i < a-1; i++){

                w = nstr(sc);
                String[] www = w.split("");

                if (list.contains(w)){
                    flag = false;
                    break;
                }

                if (stock.equals(www[0])){
                    list.add(w);
                }else {
                    flag = false;
                    break;
                }
                stock = www[www.length-1];
            }

            if (flag) {
                out.println("Yes");
            }else {
                out.println("No");
            }
        }
    }

    // method
    static int nint(Scanner sc) {
        return Integer.parseInt(sc.next());
    }

    static long nlong(Scanner sc) {
        return Long.parseLong(sc.next());
    }

    static double ndouble(Scanner sc) {
        return Double.parseDouble(sc.next());
    }

    static float nfloat(Scanner sc) {
        return Float.parseFloat(sc.next());
    }

    static String nstr(Scanner sc) {
        return sc.next();
    }

    static long[] longLine(Scanner sc, int size) {
        long[] lLine = new long[size];
        for (int i = 0; i < size; i++) {
            lLine[i] = nlong(sc);
        }
        return lLine;
    }

    static int[] intLine(Scanner sc, int size) {
        int[] iLine = new int[size];
        for (int i = 0; i < size; i++) {
            iLine[i] = nint(sc);
        }
        return iLine;
    }

    static String[] strLine(Scanner sc, int size) {
        String[] strLine = new String[size];
        for (int i = 0; i < size; i++) {
            strLine[i] = nstr(sc);
        }
        return strLine;
    }

    static long maxFromList(List<Long> longList) {
        return longList.stream().max(Comparator.naturalOrder()).get();
    }

    static long minFromList(List<Long> longList) {
        return longList.stream().min(Comparator.naturalOrder()).get();
    }

    public static int sumDigits(int n) {
        int sum = 0;
        while (n != 0) {
            sum += n % 10;
            n /= 10;
        }
        return sum;
    }

    public static long sumDigits(long n) {
        long sum = 0;
        while (n != 0) {
            sum += n % 10;
            n /= 10;
        }
        return sum;
    }

    static List<Integer> getIntegerList(Scanner sc, int size) {
        List<Integer> list = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            list.add(nint(sc));
        }
        return list;
    }

    static List<Long> getLongList(Scanner sc, int size) {
        List<Long> list = new ArrayList<>();
        for (int i = 0; i < size; i++) {
            list.add(nlong(sc));
        }
        return list;
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz