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: ['951', 'l', '4331', 'm', '3889', 'd', 'N', 'I', 'n', 'y', '6421', 'D']

951, 12, 4331, 13, 3889, 4, 14, 9, 14, 25, 6421, 4