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: ['5891', '3457', 'M', 'f', 'n', 'T', '6963', '9871', '3577', 'D', 'Y', 't', 'S', '6069', 'r', 'D', '2579', '2043', '6409', 'k', '7897', 't', 'X', '1609', 'I']

5891, 3457, 13, 6, 14, 20, 6963, 9871, 3577, 4, 25, 20, 19, 6069, 18, 4, 2579, 2043, 6409, 11, 7897, 20, 24, 1609, 9