/**
 * A class for printing a column of X's. 
 */ 
public class ColOfX 
  {
  public static void main(String[] argv) 
    {
    /*
     * Get the number of columns from the command line argument.
     * Since the command line argument is a String, convert it to
     * an int using Integer.parseInt.
     */
    int numCols = Integer.parseInt(argv[0]);

    /*
     * In a loop to repeat for the desired number of columns, print out
     * an X with a newline. We use System.out.println to print with newline.
     */
    for (int i = 1; i <= numCols; i++) 
      {
      System.out.println("X");
      }
    }
  }