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: ['P', '7869', 'm', '8649', 'v', '645', '4805', '6809', 'O', 'k', '9239', 'q', '2291']

16, 7869, 13, 8649, 22, 645, 4805, 6809, 15, 11, 9239, 17, 2291