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: ['4239', '1613', 'J', 'S', '7047', '7769', 'O', 's', '8479', '3551', 'R', 'a', '6555', '9027', '9549', '4833', '3173', 'L', 't', '4293', '2603', 'Y']

4239, 1613, 10, 19, 7047, 7769, 15, 19, 8479, 3551, 18, 1, 6555, 9027, 9549, 4833, 3173, 12, 20, 4293, 2603, 25