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: ['h', '507', 'f', 'R', '1361', '9759', '6765', 'T', '6579', 'H', '7557', '8803', 'C', '4453', '2503']

8, 507, 6, 18, 1361, 9759, 6765, 20, 6579, 8, 7557, 8803, 3, 4453, 2503