Social Handle Case Collision

A legacy social media system allows users to create handles with any casing, but a new policy treats handles as case-insensitive. You need to find how many 'unique' handles (lowercase version) are currently being used by more than one distinct casing variation. Input Format: A single line of space-separated strings representing all existing handles. Output Format: An integer count of lowercase handle strings that map to at least two different original casing variations. Example: Input: Alice ALICE bob Bob Charlie Output: 2 (Explanation: 'alice' has variations 'Alice' and 'ALICE'. 'bob' has 'bob' and 'Bob'. 'charlie' only has one variation. Total is 2.)