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: ['4481', '3957', 'l', '257', 'Y', '6271', 'a', 'a', '9103', '5057', 'g', '8273', '1475', '3583', '3399', 'j', 'O', 'I', '2499', '8301', 'a', 'H', 'l', '903', 'n', '8951', 'U', 'm', 'i', 'R', '6215', 'l', 'f', '407', 'F', '9303']

4481, 3957, 12, 257, 25, 6271, 1, 1, 9103, 5057, 7, 8273, 1475, 3583, 3399, 10, 15, 9, 2499, 8301, 1, 8, 12, 903, 14, 8951, 21, 13, 9, 18, 6215, 12, 6, 407, 6, 9303