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: ['8415', '4547', 'j', 'y', '5877', '75', 'J', 'P', 'O', 'S', '6211', '3113', '7253', '7621']

8415, 4547, 10, 25, 5877, 75, 10, 16, 15, 19, 6211, 3113, 7253, 7621