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: ['B', 'S', '303', 'O', '4063', '9103', '7879', '7081', 'R', 'k', '1489', 'a', '9175', 'R', '5709', 'Q', '8553']

2, 19, 303, 15, 4063, 9103, 7879, 7081, 18, 11, 1489, 1, 9175, 18, 5709, 17, 8553