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: ['S', '433', '2129', 'U', 's', '9851', '9623', '1291', '3813', '1907', 'h', '1589', 'p']

19, 433, 2129, 21, 19, 9851, 9623, 1291, 3813, 1907, 8, 1589, 16