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: ['o', '3375', '5751', '5135', '4383', '5981', '3625', 'L', 'i', '1275', 'J', '2019', '2369', '5523', '9505', 'x', 'U', 'b', 'w']

15, 3375, 5751, 5135, 4383, 5981, 3625, 12, 9, 1275, 10, 2019, 2369, 5523, 9505, 24, 21, 2, 23