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: ['6139', '1017', '9317', '1229', 'u', '4985', 'n', 'D', '8699', 'o', '9029', '4733', '4121', 'q', '3619', 'V', '2299', '9145', 'V']

6139, 1017, 9317, 1229, 21, 4985, 14, 4, 8699, 15, 9029, 4733, 4121, 17, 3619, 22, 2299, 9145, 22