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: ['l', 'r', '251', '1771', '6379', 'A', '7435', 'C', '6229', 'X', '7207', '3427', 'D', 'F', 'O', '9039', '8979', '8555', 'D', 'C', 'F', '2659', 'J', 'l']

12, 18, 251, 1771, 6379, 1, 7435, 3, 6229, 24, 7207, 3427, 4, 6, 15, 9039, 8979, 8555, 4, 3, 6, 2659, 10, 12