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: ['Y', 'I', 'B', 'U', 'f', '5835', 'l', 'D', '3619', '5459', 'w', 'N', 'D', '7649', 'L', '8443', 'l', 's', 'm', 'K', 'L', '1997', '8041', '5875', 'L', 'r']

25, 9, 2, 21, 6, 5835, 12, 4, 3619, 5459, 23, 14, 4, 7649, 12, 8443, 12, 19, 13, 11, 12, 1997, 8041, 5875, 12, 18