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', 'U', 'b', 'k', '1905', '2291', 'J', '7679', 'X', 'e', '1939', 'h', '2231', 'U', 'r', 'X', 'n']

6, 21, 2, 11, 1905, 2291, 10, 7679, 24, 5, 1939, 8, 2231, 21, 18, 24, 14