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: ['A', '5559', '2573', 'F', '8233', 'A', 'F', 'u']

1, 5559, 2573, 6, 8233, 1, 6, 21