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: ['6307', '8099', '9757', 'y', 'I', '2371', '5105', '1163', '7941', '9695', '1083', '8577', 'L', 'I', 'R', '2583', '3605', '3855', 'G', '6545', '5839']

6307, 8099, 9757, 25, 9, 2371, 5105, 1163, 7941, 9695, 1083, 8577, 12, 9, 18, 2583, 3605, 3855, 7, 6545, 5839