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: ['6587', '3905', 'j', '6245', '2463', '8517', 'O', 'B', '9815', '9281', 'X', '4009', '8827', 'n', 'V', 'U', 'm', '4167', '1833']

6587, 3905, 10, 6245, 2463, 8517, 15, 2, 9815, 9281, 24, 4009, 8827, 14, 22, 21, 13, 4167, 1833