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: ['L', '4809', '7673', 'q', '7383', 'r', 'X', 'Z', '2693', '631', '6625', 'R', 'X', '3559', '2491', 'N', '2929', '7509', 'B']

12, 4809, 7673, 17, 7383, 18, 24, 26, 2693, 631, 6625, 18, 24, 3559, 2491, 14, 2929, 7509, 2