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', '3647', 'L', '3865', '9933', 'c', 'r']

18, 3647, 12, 3865, 9933, 3, 18