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: ['k', 's', 'J', 'o', 'M', 'P', 'f', 'C', 'a', 'q', 'u', '4787', '6357', 'z', 'R', 'q', '9351', '7529', '1167', 'g', '7553', 'r']

11, 19, 10, 15, 13, 16, 6, 3, 1, 17, 21, 4787, 6357, 26, 18, 17, 9351, 7529, 1167, 7, 7553, 18