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: ['U', 'l', 'A', 'f', '4359', '4811', 'B', '625', 'u', '9881', 'h', 'X', 'Y', '4873', '6263', '6891', '5159', 'U', '8687', '3513', '5875', '9589', 'n', '2911', '8023', '6693', '5143', 'T', 'E', 'B', 'k', '5733', 'c', '7515', '659', '8069', 'S']

21, 12, 1, 6, 4359, 4811, 2, 625, 21, 9881, 8, 24, 25, 4873, 6263, 6891, 5159, 21, 8687, 3513, 5875, 9589, 14, 2911, 8023, 6693, 5143, 20, 5, 2, 11, 5733, 3, 7515, 659, 8069, 19