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: ['S', 'P', 's', '6627', '2895', '4539', 'A', 'K', '1841', '5827', '5637', '3349', '1479', 'L', '6451', '9541']

19, 16, 19, 6627, 2895, 4539, 1, 11, 1841, 5827, 5637, 3349, 1479, 12, 6451, 9541