import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    }

} import java.util.*; util.* java public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    }

} Main public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    } main {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    } Scanner sc = new Scanner(System.in); sc new Scanner(System.in) int n = sc.nextInt(); n sc.nextInt() sc.nextInt sc String ans = "Yes"; ans "Yes" String[] w = new String[n]; w new String[n] n for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        } {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        } w[i] = sc.next() w[i] w i sc.next() sc.next sc for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            } int j = 0; int j = 0; j 0 j < i j i j++ j++ j {
                if (w[j].equals(w[i])) ans = "No";
            } {
                if (w[j].equals(w[i])) ans = "No";
            } if (w[j].equals(w[i])) ans = "No"; w[j].equals(w[i]) w[j].equals w[j] w j w[i] w i ans = "No" ans "No" for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        } int i = 1; int i = 1; i 1 i < n i n i++ i++ i {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        } {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        } if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No"; w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0) w[i-1].charAt(w[i-1].length()-1) w[i-1].charAt w[i-1] w i-1 i 1 w[i-1].length()-1 w[i-1].length() w[i-1].length w[i-1] w i-1 i 1 1 w[i].charAt(0) w[i].charAt w[i] w i 0 ans = "No" ans "No" System.out.println(ans) System.out.println System.out System System.out ans String[] args args public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    }

} public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    }

} Main
import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        String ans = "Yes";
        String[] w = new String[n];
        for (int i = 0; i < n; i++) {
            w[i] = sc.next();
            for (int j = 0; j < i; j++) {
                if (w[j].equals(w[i])) ans = "No";
            }
        }
        for (int i = 1; i < n; i++) {
            if (w[i-1].charAt(w[i-1].length()-1) != w[i].charAt(0)) ans = "No";
        }
        System.out.println(ans);
    }

}