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: ['6509', 'J', 'p', '1239', 'n', '5123', '2391', '8715', 'G', 'v', 'g', 'h', '1203', '9327', 'O', '6897']

6509, 10, 16, 1239, 14, 5123, 2391, 8715, 7, 22, 7, 8, 1203, 9327, 15, 6897