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: ['D', '5607', '5951', 's', '4559', '6021', 'C', 'U', 'j', '4353', '2771', 's', '8379', '4863', 'S', '5229', '381', 'w', 'G', '5647']

4, 5607, 5951, 19, 4559, 6021, 3, 21, 10, 4353, 2771, 19, 8379, 4863, 19, 5229, 381, 23, 7, 5647