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', 'd', '8597', '2949', 'L', 'b', 'z', 'q', 'T', 'm', 'z', 'R', 'H', 'a', 'P', '6519', 's']

20, 4, 8597, 2949, 12, 2, 26, 17, 20, 13, 26, 18, 8, 1, 16, 6519, 19