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: ['P', 'P', 'K', '5909', 'd', '9173', 'a', '477', 'W', '3391', '8545', '8209', 'R', 'b', '9465', 'p']

16, 16, 11, 5909, 4, 9173, 1, 477, 23, 3391, 8545, 8209, 18, 2, 9465, 16