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: ['9515', 'l', '1381', 'H', '2489', 'Y', 'k', '5329', 'S', 'F', 'b', '6007', 'v', 'P', '5209', 'x', 'F', 'p', '3879', 'S', '4659', '1059']

9515, 12, 1381, 8, 2489, 25, 11, 5329, 19, 6, 2, 6007, 22, 16, 5209, 24, 6, 16, 3879, 19, 4659, 1059