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: ['t', 's', 'l', 'm', 'i', 'b', '865', '753', 'H', 'R', 'G', 'l', 'v', '1751', 'j', 's', '6765', '8115', 'W']

20, 19, 12, 13, 9, 2, 865, 753, 8, 18, 7, 12, 22, 1751, 10, 19, 6765, 8115, 23