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: ['L', 'f', '6707', 'j', 'x', 'I', '9563', 'M', '621', '8003', 'a', '6181', '1379', '8517', 't', '4599', 'h', '4673', '4897', 'J', 'G']

12, 6, 6707, 10, 24, 9, 9563, 13, 621, 8003, 1, 6181, 1379, 8517, 20, 4599, 8, 4673, 4897, 10, 7