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: ['1991', 'H', '7993', '9071', '6949', 'g', 'h', 'C', '305', 'x', '5557', '1181', 'H', '663']

1991, 8, 7993, 9071, 6949, 7, 8, 3, 305, 24, 5557, 1181, 8, 663