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', 'd', '755', 'k', 'f', '4799', '7177', '3891', 'P', 'D']

8, 4, 755, 11, 6, 4799, 7177, 3891, 16, 4