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: ['2253', '3759', '5307', '8355', 'r', '307', 'I', '5849', '7557', '1353', '3813', '5613', '2311', '477', '4439']

2253, 3759, 5307, 8355, 18, 307, 9, 5849, 7557, 1353, 3813, 5613, 2311, 477, 4439