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: ['F', '6545', 'N', '9439', '891', '2183', 'I', '7617', 'H', 'I', 'L', 'F', '3607', 'U', 'X', '4975', 'E']

6, 6545, 14, 9439, 891, 2183, 9, 7617, 8, 9, 12, 6, 3607, 21, 24, 4975, 5