content: public class TwelveDays {
      private static String[] days = new String[]{"first", "second", "third", "fourth", "fifth", "sixth", "seventh",
          "eighth", "ninth", "tenth", "eleventh", "twelfth"};
      private static String[] gifts = new String[]{
          "a Partridge in a Pear Tree.",
          "two Turtle Doves, ",
          "three French Hens, ",
          "four Calling Birds, ",
          "five Gold Rings, ",
          "six Geese-a-Laying, ",
          "seven Swans-a-Swimming, ",
          "eight Maids-a-Milking, ",
          "nine Ladies Dancing, ",
          "ten Lords-a-Leaping, ",
          "eleven Pipers Piping, ",
          "twelve Drummers Drumming, "
      };
  
      public String verse(int verseNumber) {
          StringBuilder stringBuilder = new StringBuilder("On the " + days[verseNumber - 1]
                  + " day of Christmas my true love gave to me: ");
          for (int i = verseNumber; i > 0; i--) {
              if (verseNumber != 1 && i == 1) {
                  stringBuilder.append("and ");
              }
              stringBuilder.append(gifts[i - 1]);
          }
          stringBuilder.append("\n");
          return stringBuilder.toString();
      }
  
      public String verses(int verseNumberStart, int verseNumberEnd) {
          StringBuilder stringBuilder = new StringBuilder(verse(verseNumberStart));
          for (int i = verseNumberStart + 1; i <= verseNumberEnd; i++) {
              stringBuilder.append("\n");
              stringBuilder.append(verse(i));
          }
          return stringBuilder.toString();
      }
  
      public String sing() {
          return verses(1, 12);
      }
  }
  