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: ['421', 'g', '1799', '7809', '1329', '9945', 'p', '997', '993', 'D']

421, 7, 1799, 7809, 1329, 9945, 16, 997, 993, 4