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: ['U', '7727', 'Z', '1803', 'k', 'T', '1997', 'M', '2981', 'G', 'C', '6601', '9419', 'U', 'd', '5363', '4633', 'R', 'U', '2541', '3067']

21, 7727, 26, 1803, 11, 20, 1997, 13, 2981, 7, 3, 6601, 9419, 21, 4, 5363, 4633, 18, 21, 2541, 3067