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: ['C', 'S', 'C', 'T', '4187', '8575', '405', 'N', '7281']

3, 19, 3, 20, 4187, 8575, 405, 14, 7281