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', 'y', '9429', '3645', '2593', '4787', 'G', 'y', '6017', 'T', '4029', 'p', 't', '1749', '5793', '5141', 'n', 's', '4009', 'E', '2629', '1533', 'X', '7989', 'Y', 'b', 's', '1055', 'l', '3475', '9235', '2795', '2635', 'r', 'A', '7571', '1869']

21, 25, 9429, 3645, 2593, 4787, 7, 25, 6017, 20, 4029, 16, 20, 1749, 5793, 5141, 14, 19, 4009, 5, 2629, 1533, 24, 7989, 25, 2, 19, 1055, 12, 3475, 9235, 2795, 2635, 18, 1, 7571, 1869