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: ['D', 'U', 's', '9981', 'm', '6153', 'u', 'p', '5759', '9367', 'C', '8913', 'I', 'v', '2333', 'X', 'B']

4, 21, 19, 9981, 13, 6153, 21, 16, 5759, 9367, 3, 8913, 9, 22, 2333, 24, 2