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: ['3003', '6631', 's', '5685', '2819', 'S', 'e', 'w', 'U']

3003, 6631, 19, 5685, 2819, 19, 5, 23, 21