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: ['2587', 'I', 'd', '9079', '1471', '6369', 'l', '4137', 'S', 'D', 'P', '5745', '2259', '73', 'O', '2357', '5541', '1805', '4007', '7917', '9873', 'k', 'B', '3215', '4453']

2587, 9, 4, 9079, 1471, 6369, 12, 4137, 19, 4, 16, 5745, 2259, 73, 15, 2357, 5541, 1805, 4007, 7917, 9873, 11, 2, 3215, 4453