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: ['a', '1575', '4921', 'F', '155', 'Q', 'U', '5009', '8229', '1673', 'X', '9151', 'Q', 'H', '1747', '9587', '9195', '979', '1849', '155', 'I', '3005', '2103', '101', 'D', '2489', '1229', '5179', 'l', 'k', 'K', 'X', 'H', 'I', '3725', 's']

1, 1575, 4921, 6, 155, 17, 21, 5009, 8229, 1673, 24, 9151, 17, 8, 1747, 9587, 9195, 979, 1849, 155, 9, 3005, 2103, 101, 4, 2489, 1229, 5179, 12, 11, 11, 24, 8, 9, 3725, 19