3137. Minimum Number of Operations to Make Word K-Periodic

You are given a string word of size n, and an integer k such that k divides n. In one operation, you can pick any two indices i and j, that are divisible by k, then replace the substring of length k starting at i with the substring of length k starting at j. That is, replace the substring word[i..i + k - 1] with the substring word[j..j + k - 1]. Return the minimum number of operations required t