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: ['2871', 'Q', 'C', 'm', 'F', 'v', 's', '7141', 'B', '1585', 'P', '7121']

2871, 17, 3, 13, 6, 22, 19, 7141, 2, 1585, 16, 7121