The Tile Pattern Finder

In a digital image represented by a grid of characters, we want to find recurring patterns. A '2x2 texture' is a 2x2 square of characters. Count how many unique 2x2 textures appear more than once in the given grid. Input Format: - Line 1: Two integers R and C (rows and columns). - Next R lines: C characters each. Output Format: - An integer representing the number of distinct 2x2 patterns that occur at least twice. Example: Input: 3 3 ABA BAB ABA Output: 1 (Explanation: The 2x2 pattern [[A,B],[B,A]] appears 4 times, but it is only 1 unique pattern.)