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: ['9559', 'Z', '3889', 'A', '251', '255', 'a', 'm', 't', 'U', '365', '2595', 't', '5547', 'x', 'F', '705', '4007']

9559, 26, 3889, 1, 251, 255, 1, 13, 20, 21, 365, 2595, 20, 5547, 24, 6, 705, 4007