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: ['J', '3671', '6727', 'U', 'J', '1009', 'l', 'b', 'i', 'D', 'L', 'M', 'I']

10, 3671, 6727, 21, 10, 1009, 12, 2, 9, 4, 12, 13, 9