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: ['T', '9907', 'l', '8259', '6639', 'X', 'o', 'P', 'f', 'L', '9239', 'd', '827', '4395', '7893', '8961', 'l', '5259', 'D', 'j', '7481', '9915']

20, 9907, 12, 8259, 6639, 24, 15, 16, 6, 12, 9239, 4, 827, 4395, 7893, 8961, 12, 5259, 4, 10, 7481, 9915