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: ['7857', 'V', 'n', 'O', '89', '2563', 'i', '9723', '43', 'Y', 'O', '777', '4697', 'c', '6593', 'O']

7857, 22, 14, 15, 89, 2563, 9, 9723, 43, 25, 15, 777, 4697, 3, 6593, 15