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: ['339', '6531', '9657', 'U', 'K', '827', '3243', '6617', '1417', 'N', 'e', 'z', '3531', 'U', '8145', 'O', '7999', '611', 'z', 'i', 'y', '5941', '1749', '3049', '1477', '975']

339, 6531, 9657, 21, 11, 827, 3243, 6617, 1417, 14, 5, 26, 3531, 21, 8145, 15, 7999, 611, 26, 9, 25, 5941, 1749, 3049, 1477, 975