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: ['4139', '1363', '165', 'C', '1345', 'U', 'V', 'L', 'D', 'R', '6145', 'P', 'f', '5671', '4455', 'S', 'j', '6331', '6759', 'q', 'V', '9749', '5151']

4139, 1363, 165, 3, 1345, 21, 22, 12, 4, 18, 6145, 16, 6, 5671, 4455, 19, 10, 6331, 6759, 17, 22, 9749, 5151