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: ['S', '7997', 'E', 'T', '1783', 'i', 'B', '371', 'u', '825', 'Y', 'R', '961', 'x', '6859', '6293', 'a', 'K', 'W', 'k', '1309', '6785', '2153', 'S', '7791', 'q']

19, 7997, 5, 20, 1783, 9, 2, 371, 21, 825, 25, 18, 961, 24, 6859, 6293, 1, 11, 23, 11, 1309, 6785, 2153, 19, 7791, 17