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: ['7281', 'X', '509', 'f', '4999', '7083', '3189', 'S', '9077', '4803', 'O', 'Q', '5899', 'X', 'Y', '3637', 'S', 'c', '2909']

7281, 24, 509, 6, 4999, 7083, 3189, 19, 9077, 4803, 15, 17, 5899, 24, 25, 3637, 19, 3, 2909