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: ['1427', '5867', '7035', '6159', 'a', '1957', '1231', 'H', 'n', '9687', 'x', '9709', '1939']

1427, 5867, 7035, 6159, 1, 1957, 1231, 8, 14, 9687, 24, 9709, 1939