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', 'a', '3439', 'D', '8863', 'b', '2363', 'G', '259', '9053']

15, 1, 3439, 4, 8863, 2, 2363, 7, 259, 9053