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: ['i', '6989', 's', 'r', '4619', 'G', '8469', 't', '3417', '7563', 'S', 'g', 'G', 'P', 'l', '5439', 'N', 'x', 'b', '4605', 'z', 'S', 'w', '4555', 'v', '8139', 'n', '8297', 'O', '6591']

9, 6989, 19, 18, 4619, 7, 8469, 20, 3417, 7563, 19, 7, 7, 16, 12, 5439, 14, 24, 2, 4605, 26, 19, 23, 4555, 22, 8139, 14, 8297, 15, 6591