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: ['3857', 'u', 'k', 'x', '5315', 'a', 'r', '6871', 'q', 'w', 'J', 'c', 's', '9307', '9325', '297', 'g', 'P', 'G', 'A', '4155', '9307', '1055', '4619', '1521', '6653', 'y', '8831', '8445', 'g', 'l', 'C', 'a', 'o']

3857, 21, 11, 24, 5315, 1, 18, 6871, 17, 23, 10, 3, 19, 9307, 9325, 297, 7, 16, 7, 1, 4155, 9307, 1055, 4619, 1521, 6653, 25, 8831, 8445, 7, 12, 3, 1, 15