doesn't match case-insensitive spec

Issue with problem statement

There are inconsistencies between the problem description and the test cases.

1. The problem statement says, "The letters should be compared case-insensitive," but the tests only pass if the sorting is case-sensitive.

2. The the following sentence in the problem statement is redundant: "If both letters are the same, order them normally (lexicographically), again, case-insensitive". Lexicographical ordering already handles ties without needing a separate case-insensitivity clause.

Please clarify whether the sorting should be case-sensitive or case-insensitive.