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: ['W', '2309', 'j', 'q', '8469', '8331', 'K', 'U', '7667', 'l', '3515']

23, 2309, 10, 17, 8469, 8331, 11, 21, 7667, 12, 3515