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: ['r', '8395', '9543', 'r', '8255', '6465', '8489', 'A', '9873', 'c', '4593', 'p', 'L', '4503', 'A', '8793']

18, 8395, 9543, 18, 8255, 6465, 8489, 1, 9873, 3, 4593, 16, 12, 4503, 1, 8793