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: ['l', '4137', 'B', '8409', 'I', '2745', '8201', 'g', 'z', '5981', 'U', 'H', 'k', '559', '3601', 's', '1133']

12, 4137, 2, 8409, 9, 2745, 8201, 7, 26, 5981, 21, 8, 11, 559, 3601, 19, 1133