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: ['z', '4841', 'O', '5933', '5105', '8763', '1923', 'Y', '7149', '3157', 'O', '9401', 'K', 'l', '7541', 's', 'M', 'O']

26, 4841, 15, 5933, 5105, 8763, 1923, 25, 7149, 3157, 15, 9401, 11, 12, 7541, 19, 13, 15