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: ['r', 'W', 'o', '7545', 'W', '3663', '9999', 'S', '7759', 'W']

18, 23, 15, 7545, 23, 3663, 9999, 19, 7759, 23