Kth Bit Activation

Write a function that takes an integer n and an integer k. Your task is to find and return the integer generated by activating the k-th bit of the binary representation of n. If the k-th bit is already set, return n itself. If not, return the modified integer. Example: Input: 5 2 Output: 7 Explanation: The binary representation of 5 is 101. Activating the 2nd bit (counting from 0) results in 111, which is 7.