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: ['b', 'D', '4039', '525', '9291', 'K', 'G', '5879', 'U', 'u', '8103', 'y', 'A', '3921']

2, 4, 4039, 525, 9291, 11, 7, 5879, 21, 21, 8103, 25, 1, 3921