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: ['9907', '7315', '4877', '7953', 'K', '2665', '1001', '7031', 'm', 'l', 'f', '3821', 'm', '7561', 'i', 'J', 'N', 'Q', '4781', '2357', 'D', 'F']

9907, 7315, 4877, 7953, 11, 2665, 1001, 7031, 13, 12, 6, 3821, 13, 7561, 9, 10, 14, 17, 4781, 2357, 4, 6