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: ['t', 'l', 'h', '9711', 'P', 'i', '2121', '6569']

20, 12, 8, 9711, 16, 9, 2121, 6569