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: ['R', 'O', '1263', '5821', 'w', 'k', '7949', '6761', '2789', '9045', 'B', 'b', 'M', '5667', '8549', 'y', 'i', '8143', 'K', '9841', '4857', 'f', 'd', '1987', 'G', '2175', 'U', '7107', '1431', '2053', 'u', 'X', 'v', 'D', 'a', 'N', 'v', 'A', 'n', '2775']

18, 15, 1263, 5821, 23, 11, 7949, 6761, 2789, 9045, 2, 2, 13, 5667, 8549, 25, 9, 8143, 11, 9841, 4857, 6, 4, 1987, 7, 2175, 21, 7107, 1431, 2053, 21, 24, 22, 4, 1, 14, 22, 1, 14, 2775