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: ['o', '5137', 'u', 'r', '3795', '3335', '5477', '9803', 'F', '9887', 'S', '6305', 'G', '9589', 'D', '8615', '9045', '401']

15, 5137, 21, 18, 3795, 3335, 5477, 9803, 6, 9887, 19, 6305, 7, 9589, 4, 8615, 9045, 401