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: ['3951', '3373', '4875', 'a', '385', 'G', 'T', 'L', 'y', '997', 'C', '2883', 'X', '943', 'D', '9483', 'y', 'v', 'C', '559']

3951, 3373, 4875, 1, 385, 7, 20, 12, 25, 997, 3, 2883, 24, 943, 4, 9483, 25, 22, 3, 559