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: ['x', 'B', 'X', 'U', 'v', '6843', '721', 'g', 'r', '3883', 'u', '8827', '2039', '8113', 'S', '9767', '3787']

24, 2, 24, 21, 22, 6843, 721, 7, 18, 3883, 21, 8827, 2039, 8113, 19, 9767, 3787