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: ['615', 'N', '6125', '9071', '8477', 'H', '2499', '1821']

615, 14, 6125, 9071, 8477, 8, 2499, 1821