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', 'F', 'o', '8761', 'o', 't', '2151', '1421', '9381', 'o', '8687', 'i', 'B', '7911', '2759', 'M', '4555', '3747', '145', 'W']

12, 6, 15, 8761, 15, 20, 2151, 1421, 9381, 15, 8687, 9, 2, 7911, 2759, 13, 4555, 3747, 145, 23