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: ['W', '3099', 'Y', '2261', '7571', '6643', 'l', '7585', '6591', '9567', 'e', 'I', 'Z', '3603', 'B']

23, 3099, 25, 2261, 7571, 6643, 12, 7585, 6591, 9567, 5, 9, 26, 3603, 2