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: ['4511', 'W', '6427', '9007', '9213', 'r', '9963', 'q', '9787', 'Y', '3925', 'g', '8775', 'i', '1553', '633', 'k', '1549', 'i', '3725', '4221', 'I', '9187', '2781', '3131', 'R', 'T', '1691', '9559', 'O', '7871', '1519', 'i', 'f']

4511, 23, 6427, 9007, 9213, 18, 9963, 17, 9787, 25, 3925, 7, 8775, 9, 1553, 633, 11, 1549, 9, 3725, 4221, 9, 9187, 2781, 3131, 18, 20, 1691, 9559, 15, 7871, 1519, 9, 6