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: ['5189', 'H', 'b', 'R', 'P', '2763', 'u', '5187']

5189, 8, 2, 18, 16, 2763, 21, 5187