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: ['y', '9473', '1971', 'D', '3779', '8851', '9621', 'L', '6633']

25, 9473, 1971, 4, 3779, 8851, 9621, 12, 6633