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: ['4697', '3121', '3407', 'B', '7405', '6855', '7757', 'U', '5299', '3001', '2769', '6907', 'y', '3455', 'F', 'O', 'p', '4431', 'Q', 'C', '2905']

4697, 3121, 3407, 2, 7405, 6855, 7757, 21, 5299, 3001, 2769, 6907, 25, 3455, 6, 15, 16, 4431, 17, 3, 2905