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: ['7781', 'O', 'M', 's', '2161', 'L', 'z', '2361', '4839', 'N', 'q', 'm', '4611', 'a', '3891', '4443', '7683', '4435', 'Y', '3757', 'n', 'C']

7781, 15, 13, 19, 2161, 12, 26, 2361, 4839, 14, 17, 13, 4611, 1, 3891, 4443, 7683, 4435, 25, 3757, 14, 3