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: ['S', '5833', '8929', 'S', 'U', 'q', '2071', '5555', 'u']

19, 5833, 8929, 19, 21, 17, 2071, 5555, 21