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', '3463', 'B', '8557', 'f', 'v', 'Y', '9259', 'S', '5381', '543', '3171', 'r', '273', '7739', 'y', 'a']

12, 3463, 2, 8557, 6, 22, 25, 9259, 19, 5381, 543, 3171, 18, 273, 7739, 25, 1