import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author mikit
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    }

    static class BShiritori {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        }

    }
}
 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.HashSet; HashSet java.util import java.util.Scanner; Scanner java.util import java.util.Set; Set java.util public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    }

    static class BShiritori {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        }

    }
} Main public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    } main {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    } InputStream inputStream = System.in; inputStream System.in System System.in OutputStream outputStream = System.out; outputStream System.out System System.out Scanner in = new Scanner(inputStream); in new Scanner(inputStream) PrintWriter out = new PrintWriter(outputStream); out new PrintWriter(outputStream) BShiritori solver = new BShiritori(); solver new BShiritori() solver.solve(1, in, out) solver.solve solver 1 in out out.close() out.close out String[] args args static class BShiritori {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        }

    } BShiritori public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        } solve {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        } int n = in.nextInt(); n in.nextInt() in.nextInt in Set<String> words = new HashSet<>(); words new HashSet<>() char last = 0; last 0 for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            } int i = 0; int i = 0; i 0 i < n i n i++ i++ i {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            } {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            } String w = in.next(); w in.next() in.next in if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                } words.contains(w) || (last > 0 && last != w.charAt(0)) words.contains(w) words.contains words w (last > 0 && last != w.charAt(0)) last > 0 last 0 last != w.charAt(0) last w.charAt(0) w.charAt w 0 {
                    out.println("No");
                    return;
                } out.println("No") out.println out "No" return; words.add(w) words.add words w last = w.charAt(w.length() - 1) last w.charAt(w.length() - 1) w.charAt w w.length() - 1 w.length() w.length w 1 out.println("Yes") out.println out "Yes" int testNumber testNumber Scanner in in PrintWriter out out public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    }

    static class BShiritori {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        }

    }
} public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    }

    static class BShiritori {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        }

    }
} Main
import java.io.OutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.PrintWriter;
import java.util.HashSet;
import java.util.Scanner;
import java.util.Set;

/**
 * Built using CHelper plug-in
 * Actual solution is at the top
 *
 * @author mikit
 */
public class Main {
    public static void main(String[] args) {
        InputStream inputStream = System.in;
        OutputStream outputStream = System.out;
        Scanner in = new Scanner(inputStream);
        PrintWriter out = new PrintWriter(outputStream);
        BShiritori solver = new BShiritori();
        solver.solve(1, in, out);
        out.close();
    }

    static class BShiritori {
        public void solve(int testNumber, Scanner in, PrintWriter out) {
            int n = in.nextInt();
            Set<String> words = new HashSet<>();
            char last = 0;
            for (int i = 0; i < n; i++) {
                String w = in.next();
                if (words.contains(w) || (last > 0 && last != w.charAt(0))) {
                    out.println("No");
                    return;
                }
                words.add(w);
                last = w.charAt(w.length() - 1);
            }
            out.println("Yes");
        }

    }
}

