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: ['d', '6623', '6903', 'r', 'M', '9553', 'r', 'k', 'M', '6275', 'F', '6219']

4, 6623, 6903, 18, 13, 9553, 18, 11, 13, 6275, 6, 6219