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', '4669', 'O', 'Y', '3447', '7555', 'P', 'c', '3677', '4059', '243', 'G']

20, 4669, 15, 25, 3447, 7555, 16, 3, 3677, 4059, 243, 7