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: ['p', 'T', 'P', '9783', 'U', '9379', 'I', '8115', 'c', '3675', 'x', 'w', 'a', '6543', 'n', 'V', '1573', '5973', '6139', 'F', 'u', '505', 'A', 'N', 'i', 'N', '1553', '5881', '7485', '7891', '3721', 'N', 'N', '4321', 'l', 'L', '8591', '5001', '2557']

16, 20, 16, 9783, 21, 9379, 9, 8115, 3, 3675, 24, 23, 1, 6543, 14, 22, 1573, 5973, 6139, 6, 21, 505, 1, 14, 9, 14, 1553, 5881, 7485, 7891, 3721, 14, 14, 4321, 12, 12, 8591, 5001, 2557