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: ['t', '855', 'x', 'E', '6569', 'P', '2985', '767', '6427', '4061', '2493', 'Z', 'u', '8289', '5901', '3755', 'd', '4015', '1181']

20, 855, 24, 5, 6569, 16, 2985, 767, 6427, 4061, 2493, 26, 21, 8289, 5901, 3755, 4, 4015, 1181