Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['809', '2295', '9207', 'W', '5209', '6785', 'w', '8983', 'm', 'k', '2527', '7137', 'U']

809, 2295, 9207, 23, 5209, 6785, 23, 8983, 13, 11, 2527, 7137, 21