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: ['3603', 'd', '4411', '2963', 'U', '4683', 'O', '8397', '8685']

3603, 4, 4411, 2963, 21, 4683, 15, 8397, 8685