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: ['f', '4281', '8273', '6921', 'W', '2941', '7625', '761', 'l', '231', '6193', 'O', 'S', 'j', 'f', 'O', 'd', '1769', 'B', 'E', '29', 'e', 'J', '6603', 'd', 'f', 'K', '9145', '8747', 'c', 'k', '8073', '7251', '8703', '7367', '3737', '7523', 'Z', '7489', 'U']

6, 4281, 8273, 6921, 23, 2941, 7625, 761, 12, 231, 6193, 15, 19, 10, 6, 15, 4, 1769, 2, 5, 29, 5, 10, 6603, 4, 6, 11, 9145, 8747, 3, 11, 8073, 7251, 8703, 7367, 3737, 7523, 26, 7489, 21