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: ['4835', '8651', '8903', '6559', '1699', '7387', '671', 'R', 'F']

4835, 8651, 8903, 6559, 1699, 7387, 671, 18, 6