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: ['H', 'h', 'B', '7499', 'N', '1039', 'O', '2769', 'T', '3331', '7283', '8659', 'w', '3', 'n', '3781', '6853', '2077', 'X', '6449', 'v', '8363', '921', 'n', 'E', 'D', '9891']

8, 8, 2, 7499, 14, 1039, 15, 2769, 20, 3331, 7283, 8659, 23, 3, 14, 3781, 6853, 2077, 24, 6449, 22, 8363, 921, 14, 5, 4, 9891