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: ['r', 'O', '4945', 'J', '5021', '1003', '7635', 'B', 'g', '4803', '3603', 'V', '7909', 'A', '4743']

18, 15, 4945, 10, 5021, 1003, 7635, 2, 7, 4803, 3603, 22, 7909, 1, 4743