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: ['j', '4857', '8733', 'p', '8461', 'z', '7493', 'u', 'I', 'W', '919', '9875']

10, 4857, 8733, 16, 8461, 26, 7493, 21, 9, 23, 919, 9875