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: ['N', 'L', '9183', 'D', '3059', 'A', 's', 'E', 'o', '1687', 'J', 'u', 'L', '6501', 'i', 't', '1139', 'm']

14, 12, 9183, 4, 3059, 1, 19, 5, 15, 1687, 10, 21, 12, 6501, 9, 20, 1139, 13