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: ['U', '1861', 'T', '6575', '901', '8539', '4819', 'w']

21, 1861, 20, 6575, 901, 8539, 4819, 23