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: ['U', '9653', 'z', '7433', 'V', '5457', '1125', '4171', '9871', 'I', 'v', '535', 'B', '2723', 'J', '5307', '1987', '653', 's', 'a', 'H']

21, 9653, 26, 7433, 22, 5457, 1125, 4171, 9871, 9, 22, 535, 2, 2723, 10, 5307, 1987, 653, 19, 1, 8