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: ['v', '5721', 'R', '5747', 'n', '9641', 'C', 'X', '4453', 'p', 'k', '409', '8615', 'M', '4689', 'f', 'B', 'Y']

22, 5721, 18, 5747, 14, 9641, 3, 24, 4453, 16, 11, 409, 8615, 13, 4689, 6, 2, 25