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: ['7517', '8453', 'K', '5181', '8495', '2733', 'c', 'F', '981', '4165', '9013', 'u', '3107', 'n', 'd', '9821', '8661', '911', 'C', 'd', '3689', 'T', 'E', '9633', 'h', 'l', '5491', 'R']

7517, 8453, 11, 5181, 8495, 2733, 3, 6, 981, 4165, 9013, 21, 3107, 14, 4, 9821, 8661, 911, 3, 4, 3689, 20, 5, 9633, 8, 12, 5491, 18