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: ['7057', 'H', '6403', '4097', 'R', 's', 'F', 'u']

7057, 8, 6403, 4097, 18, 19, 6, 21