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: ['S', '5741', 'f', 'S', '2111', '1551', '1959', 'a', '2965', 'Z', '6745', '8375', 'G']

19, 5741, 6, 19, 2111, 1551, 1959, 1, 2965, 26, 6745, 8375, 7