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: ['b', 'a', 'v', 'W', 'R', '2221', 'N', '9463', 'Z', 'd', 'u', '9345']

2, 1, 22, 23, 18, 2221, 14, 9463, 26, 4, 21, 9345