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: ['603', '3809', '6749', 'M', 'q', 'T', 'j', '2931', 's', 'c', 'm', '1355', 'X', 'O', '5121', 'E', '893', 'D']

603, 3809, 6749, 13, 17, 20, 10, 2931, 19, 3, 13, 1355, 24, 15, 5121, 5, 893, 4