public static Matrix scanMatrix() { // 输入矩阵
    int i, j;
    Matrix matrix = new Matrix();
    Scanner scanner = new Scanner(System.in);

    matrix.setLine(scanner.nextInt());
    matrix.setRow(scanner.nextInt());
    matrix.setAccuracy(scanner.nextDouble());
    for (i = 0; i < matrix.getLine(); i++) {
      for (j = 0; j < matrix.getRow(); j++) matrix.setElement(i, j, scanner.nextDouble());
    }
    return matrix;
  }
  public static void main(String[] args) {
    int i = 4;
    double d = 4.0;
    String s = "HackerRank ";

    Scanner scan = new Scanner(System.in);

    /* Declare second integer, double, and String variables. */
    int j;
    double e;
    String t;
    /* Read and save an integer, double, and String to your variables.*/
    j = scan.nextInt();
    e = scan.nextDouble();
    scan.nextLine();
    t = scan.nextLine();
    /* Print the sum of both integer variables on a new line. */
    System.out.println(i + j);
    /* Print the sum of the double variables on a new line. */
    System.out.println(d + e);
    /* Concatenate and print the String variables on a new line;
    the 's' variable above should be printed first. */
    System.out.println(s + t);

    scan.close();
  }