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: ['1513', '5009', 'c', 'm', '9423', '797', 'I', '861', '9707', 'E', '8401', '5451', 'B', 'X', '1883', 'o']

1513, 5009, 3, 13, 9423, 797, 9, 861, 9707, 5, 8401, 5451, 2, 24, 1883, 15