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: ['p', 'C', 'y', '5945', '4163', 'I', '999', 'I']

16, 3, 25, 5945, 4163, 9, 999, 9