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: ['i', '1449', 'k', '2027', 'i', '6453', '2405', '5229', 'R', '1253', '9033', 'P', 'd', '8819', 'h', 'Y', 'U', '7749', '4337', 'Y', '1989', '2961', '7993', '405', 'I', '5791']

9, 1449, 11, 2027, 9, 6453, 2405, 5229, 18, 1253, 9033, 16, 4, 8819, 8, 25, 21, 7749, 4337, 25, 1989, 2961, 7993, 405, 9, 5791