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: ['y', 'b', '3509', 't', '3493', 'm']

25, 2, 3509, 20, 3493, 13