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: ['6603', '3879', 'X', 'l', '2099', '4309', '1265', '6071', 'Q', 'S', '2081', 'd']

6603, 3879, 24, 12, 2099, 4309, 1265, 6071, 17, 19, 2081, 4