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: ['5787', '5663', '5621', '2315', '9419', 'r', 'X', 'p', '7165', 'K', '3495', 'l', 'r', 'b', '3529', '9819', 'B', 'g', 'x', '403', 'b', 'Y', 't']

5787, 5663, 5621, 2315, 9419, 18, 24, 16, 7165, 11, 3495, 12, 18, 2, 3529, 9819, 2, 7, 24, 403, 2, 25, 20