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: ['4213', 'a', 'X', '7319', '2685', '351', 'e', 'r', '9553', 'm', 'B', '665', 'a']

4213, 1, 24, 7319, 2685, 351, 5, 18, 9553, 13, 2, 665, 1