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: ['1205', 'O', '6757', 'N', 'E', 's', '757', 'h', 'l', 'S', 'Q', 't', '2159', '6771', 'P', 'l', '5011', '7679', 'c', '8181', '6729']

1205, 15, 6757, 14, 5, 19, 757, 8, 12, 19, 17, 20, 2159, 6771, 16, 12, 5011, 7679, 3, 8181, 6729