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: ['J', '5279', 'O', '4829', '5047', '459', '2579', 'U', '31', '6125', 'B', 't', '6493', '1043']

10, 5279, 15, 4829, 5047, 459, 2579, 21, 31, 6125, 2, 20, 6493, 1043