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: ['3383', 'h', 'Y', '6003', '4639', '8421', '5911', 'b', 'm', '7517', 'U', 'B', '4053', '7153', 'u', '3699', '5535', '3317', '2945', '6643', '6777', '5875', '5297', '4757', 'E']

3383, 8, 25, 6003, 4639, 8421, 5911, 2, 13, 7517, 21, 2, 4053, 7153, 21, 3699, 5535, 3317, 2945, 6643, 6777, 5875, 5297, 4757, 5