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: ['9573', '5291', 'V', '1763', 'H', '9979', 'Y', '4453', 'E', 'b', '3311', '7357', 'c', '8721', 'y', '6855']

9573, 5291, 22, 1763, 8, 9979, 25, 4453, 5, 2, 3311, 7357, 3, 8721, 25, 6855