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: ['5421', '8725', 'H', '8913', '4773', '3575', '5205', '5801', 'H', '3625', 'z', 'T', 't', '6309', 'b', '5279', 'Y', 'I', 'C', '6091', '369', 'r']

5421, 8725, 8, 8913, 4773, 3575, 5205, 5801, 8, 3625, 26, 20, 20, 6309, 2, 5279, 25, 9, 3, 6091, 369, 18