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: ['u', '8807', 'z', '8527', '9447', 'i', 'L', '7665', 'M', 'a', 'Z', '239']

21, 8807, 26, 8527, 9447, 9, 12, 7665, 13, 1, 26, 239