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: ['E', '6535', '687', '4621', '8015', '9731', '8123', '3787', 'I']

5, 6535, 687, 4621, 8015, 9731, 8123, 3787, 9