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', '6243', 'G', 'V', 'K', '6277', 'c', '9637', 'B', 'i', 'U', '3459', 'L']

10, 6243, 7, 22, 11, 6277, 3, 9637, 2, 9, 21, 3459, 12