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: ['M', 'H', 'D', '9421', '955', 'C', 'x', '4731', '2847', 'J', '6887', '2023', '6135', '8075']

13, 8, 4, 9421, 955, 3, 24, 4731, 2847, 10, 6887, 2023, 6135, 8075