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: ['T', 'U', '9787', '1271', '9349', '2503', '4579', 'A', '5811', '3909', 'y', '8117']

20, 21, 9787, 1271, 9349, 2503, 4579, 1, 5811, 3909, 25, 8117