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: ['3893', '871', '4431', '8253', 'u', '1579', 'I', '5665', '7581']

3893, 871, 4431, 8253, 21, 1579, 9, 5665, 7581