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: ['z', 'l', 'c', '807', 'a', 'L', 'A', 'C', '6341', 'c', 'Q', 'W', 'm', '149', 'c', 'B']

26, 12, 3, 807, 1, 12, 1, 3, 6341, 3, 17, 23, 13, 149, 3, 2