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: ['7691', '1641', 'H', '3459', 'R', '3321']

7691, 1641, 8, 3459, 18, 3321