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: ['L', 'H', 'O', 'i', '4747', 'p', '9811', '2939', '8407', 'P', 'r', '9389', 'n']

12, 8, 15, 9, 4747, 16, 9811, 2939, 8407, 16, 18, 9389, 14