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: ['1789', '1187', '4717', '9073', 'z', '313', '7769', 'P', 'O', 'O', 'G', '7477', '3105', '6757', 't', '1221', 'I', 'b', '5429']

1789, 1187, 4717, 9073, 26, 313, 7769, 16, 15, 15, 7, 7477, 3105, 6757, 20, 1221, 9, 2, 5429