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: ['3643', '793', '2445', 'U', 'O', '6551', '1439', '9983', 'F', '7091', '2113', 'S', 'l', '2889', 'f', 'b', 'a', 'Y', '3693', 'L', 'F', 'r', '7861', 'r', '9343', '6247', 'G', '7407', '3303', 'w', 'j', '2757', '6645', 'l', 'd', '6469', 'O', 'M']

3643, 793, 2445, 21, 15, 6551, 1439, 9983, 6, 7091, 2113, 19, 12, 2889, 6, 2, 1, 25, 3693, 12, 6, 18, 7861, 18, 9343, 6247, 7, 7407, 3303, 23, 10, 2757, 6645, 12, 4, 6469, 15, 13