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', 'u', '6231', '6621', '2143', 'T', '7791', 'v', '3005', '8569']

20, 21, 6231, 6621, 2143, 20, 7791, 22, 3005, 8569