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: ['997', '3843', '5991', '5415', 'U', 'V', '619', '9381', 'a', 'o', '9493', 'M', 'E', 'g', '9989', '9243']

997, 3843, 5991, 5415, 21, 22, 619, 9381, 1, 15, 9493, 13, 5, 7, 9989, 9243