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: ['1187', '6091', 'y', '7901', '1427', '2091', '8133', 'Y', 'u', '611', '21', '1943', 'X', 'c', '8451', 'G', 'z']

1187, 6091, 25, 7901, 1427, 2091, 8133, 25, 21, 611, 21, 1943, 24, 3, 8451, 7, 26