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: ['6731', '2997', '9369', 'l', 'U', 'h', 'A', '6611', '815', '3903', 'B', '9241', 'H', 'b', '2607']

6731, 2997, 9369, 12, 21, 8, 1, 6611, 815, 3903, 2, 9241, 8, 2, 2607