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', '7403', 'c', '9661', 'l', 'O', '9671', 'V', '7499', '8789', 's', '1379', 'Y', '8175', '8383', 'g', '919', 'j', '1947', '3453', 'l', 'x', '4713', 'n']

18, 7403, 3, 9661, 12, 15, 9671, 22, 7499, 8789, 19, 1379, 25, 8175, 8383, 7, 919, 10, 1947, 3453, 12, 24, 4713, 14