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: ['P', 'S', '1641', '5621', 'P', 'H', 'E', '5235', 'W']

16, 19, 1641, 5621, 16, 8, 5, 5235, 23