import java.io.BufferedReader;
import java.io.Closeable;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Set;
import java.util.HashSet;

public class Main {
    public static void main(String[] args) throws IOException {
        try (PrintWriter writer = new PrintWriter(System.out); InputReader reader = new InputReader(System.in)) {
            solve(writer, reader);
        }
    }

    private static void solve(PrintWriter writer, InputReader reader) throws IOException {
        int n = reader.readInt();

        Set<String> saidString = new HashSet<>(n);
        String preString = reader.readLine();
        saidString.add(preString);
        for (int i = 0; i < n - 1; i++) {
            String string = reader.readLine();
            if (saidString.contains(string) || preString.codePointAt(preString.length() - 1) != string.codePointAt(0)) {
                writer.println("No");
                writer.flush();
                return;
            }

            preString = string;
            saidString.add(preString);
        }

        writer.println("Yes");
        writer.flush();
    }
}

class InputReader implements Closeable, AutoCloseable {
    private final BufferedReader br;

    InputReader(InputStream inputStream) {
        this.br = new BufferedReader(new InputStreamReader(inputStream));
    }

    String readLine() throws IOException {
        return this.br.readLine();
    }

    int readInt() throws IOException {
        return Integer.parseInt(this.readLine());
    }

    long readLong() throws IOException {
        return Long.parseLong(this.readLine());
    }

    double readDouble() throws IOException {
        return Double.parseDouble(this.readLine());
    }

    String[] readStringsSplitByDelimiter(String delimiter) throws IOException {
        return this.readLine().split(delimiter);
    }

    int[] readIntsSplitByDelimiter(String delimiter) throws IOException {
        String[] strings = this.readStringsSplitByDelimiter(delimiter);

        int stringsLength = strings.length;
        int[] ints = new int[stringsLength];
        for (int i = 0; i < stringsLength; i++) {
            ints[i] = Integer.parseInt(strings[i]);
        }

        return ints;
    }

    long[] readLongsSplitByDelimiter(String delimiter) throws IOException {
        String[] strings = this.readStringsSplitByDelimiter(delimiter);

        int stringsLength = strings.length;
        long[] longs = new long[stringsLength];
        for (int i = 0; i < stringsLength; i++) {
            longs[i] = Long.parseLong(strings[i]);
        }

        return longs;
    }

    double[] readDoublesSplitByDelimiter(String delimiter) throws IOException {
        String[] strings = this.readStringsSplitByDelimiter(delimiter);

        int stringsLength = strings.length;
        double[] doubles = new double[stringsLength];
        for (int i = 0; i < stringsLength; i++) {
            doubles[i] = Double.parseDouble(strings[i]);
        }

        return doubles;
    }

    @Override
    public void close() throws IOException {
        this.br.close();
    }
}


Measured memory_bytes: 21844