In three different stores they label items. Each designation consists of five characters which comprises digits and letters of the English alphabet. Digits are considered to be repeatable in all cases. The item code is different in each store:
in the first store the label consists of two letters (they must not be the same) followed by three digits,
In another store, the label consists of one letter, followed by three digits and finally another letter (the letters can be the same),
in the third store, however, the label consists of two digits and is followed by three letters, which must not be the same.
In which store can they label the most items?
