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: ['5859', '4891', '2471', '6299', '6291', '3993', 'q', 'j', 'Y', '8919', 'U', '525', '8423']

5859, 4891, 2471, 6299, 6291, 3993, 17, 10, 25, 8919, 21, 525, 8423