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: ['I', 'X', 'X', '4639', 'z', 'e', 'I', 'D', 'k', '2519', 'V', '6487', '4557', 'F', '4131', '7383']

9, 24, 24, 4639, 26, 5, 9, 4, 11, 2519, 22, 6487, 4557, 6, 4131, 7383