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: ['7091', 'M', '4135', '9265', 'I', '7599', 'C', 'O', '3877', 'l', 'I', '9291', '419', 'B', 'I', 's', 'K', 'o', 'O', 'D', '4097', '3831', '413', '1185', 'd', '2783', 'r', '8543', '5259', '5269', 'A', 'M', 'U', 'a', '4429', '829', '2669', 'i', '9615']

7091, 13, 4135, 9265, 9, 7599, 3, 15, 3877, 12, 9, 9291, 419, 2, 9, 19, 11, 15, 15, 4, 4097, 3831, 413, 1185, 4, 2783, 18, 8543, 5259, 5269, 1, 13, 21, 1, 4429, 829, 2669, 9, 9615