import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    }
} import java.util.Arrays; Arrays java.util import java.util.Scanner; Scanner java.util public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    }
} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    } main {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int N = sc.nextInt(); N sc.nextInt() sc.nextInt sc String[] W = new String[N]; W new String[N] N String tmp; tmp for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        } int i = 0; int i = 0; i 0 i < N i N i++ i++ i {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        } {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        } tmp = sc.next() tmp sc.next() sc.next sc if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            } Arrays.asList(W).contains(tmp) Arrays.asList(W).contains Arrays.asList(W) Arrays.asList Arrays W tmp {
                System.out.println("No");
                return;
            } System.out.println("No") System.out.println System.out System System.out "No" return; W[i] = tmp W[i] W i tmp for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        } int i = 0; int i = 0; i 0 i < N - 1 i N - 1 N 1 i++ i++ i {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        } {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        } if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            } W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0) W[i].charAt(W[i].length() - 1) W[i].charAt W[i] W i W[i].length() - 1 W[i].length() W[i].length W[i] W i 1 W[i + 1].charAt(0) W[i + 1].charAt W[i + 1] W i + 1 i 1 0 {
                System.out.println("No");
                return;
            } System.out.println("No") System.out.println System.out System System.out "No" return; System.out.println("Yes") System.out.println System.out System System.out "Yes" String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    }
} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    }
} Main
import java.util.Arrays;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int N = sc.nextInt();
        String[] W = new String[N];
        String tmp;
        for (int i = 0; i < N; i++) {
            tmp = sc.next();
            //ダブっている単語があるかをチェック
            if (Arrays.asList(W).contains(tmp)) {
                System.out.println("No");
                return;
            }
            W[i] = tmp;
        }

        for (int i = 0; i < N - 1; i++) {
            if (W[i].charAt(W[i].length() - 1) != W[i + 1].charAt(0)) {
                System.out.println("No");
                return;
            }
        }

        System.out.println("Yes");


    }
}
