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: ['5285', '9287', 'W', 'P', 'G', '5519', '2257', '5737', 'D', '7935', 'o', '9681', '4969', '7105', 'U', 'A', '4759', 'o', 'f', 'L']

5285, 9287, 23, 16, 7, 5519, 2257, 5737, 4, 7935, 15, 9681, 4969, 7105, 21, 1, 4759, 15, 6, 12