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: ['9071', '3435', '1501', 't', '1369', '535', 'u', '1233', 'O']

9071, 3435, 1501, 20, 1369, 535, 21, 1233, 15