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: ['4105', '9083', 'P', 'U', 'n', 'g', '5125', 'O']

4105, 9083, 16, 21, 14, 7, 5125, 15