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: ['1493', '6123', '9599', 'i', 'r', '4879', '1949', '1397', 'S', 'm', 'H', 'N']

1493, 6123, 9599, 9, 18, 4879, 1949, 1397, 19, 13, 8, 14