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: ['L', '2559', '8563', '7277', 'c', 'U', '9159', '5511', 'K', '2765', '9709', 'i', 's', 'B', 'a', '1909', '5953', 'D', '3655', '5459', '6277', '9321']

12, 2559, 8563, 7277, 3, 21, 9159, 5511, 11, 2765, 9709, 9, 19, 2, 1, 1909, 5953, 4, 3655, 5459, 6277, 9321