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: ['k', '7849', '6543', '6845', 'P', '159', 'D', 'P', 't', '4659', 's']

11, 7849, 6543, 6845, 16, 159, 4, 16, 20, 4659, 19