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: ['7115', '3643', 'p', '4951', 'B', 'w', 'r', 'A', '5421', 's', 'F']

7115, 3643, 16, 4951, 2, 23, 18, 1, 5421, 19, 6