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: ['O', '3697', '5487', 'y', 's', '209', '1321', 'u', 'h', 'G', '9809', '2207', '6265', '1321']

15, 3697, 5487, 25, 19, 209, 1321, 21, 8, 7, 9809, 2207, 6265, 1321