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: ['o', '9291', 'x', 'P', 'Z', '6367', 'u', '2409']

15, 9291, 24, 16, 26, 6367, 21, 2409