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', 'U', '2683', '1631', 'y', '7547', '4717', 'P', '709', 'l', 'G', 'i', 'n', 'H', 't', '1811']

19, 21, 2683, 1631, 25, 7547, 4717, 16, 709, 12, 7, 9, 14, 8, 20, 1811