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: ['4227', '9243', 'S', '1581', '5155', 'l', 'U', '5999', 'H', '7475', '9415', '4443', 'k', '219', 'M', 'f', '1163', 'U', '6595', '1471', 'G', 'v', '4867', '2729']

4227, 9243, 19, 1581, 5155, 12, 21, 5999, 8, 7475, 9415, 4443, 11, 219, 13, 6, 1163, 21, 6595, 1471, 7, 22, 4867, 2729