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: ['m', 'w', '2353', 'y', '2187', '3999', 'u', '7381', 'R', 'J', '6927', 't', 'O', '6523', '1547', 'v', '7871']

13, 23, 2353, 25, 2187, 3999, 21, 7381, 18, 10, 6927, 20, 15, 6523, 1547, 22, 7871