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: ['2831', 'N', 'X', '1349', 'K', 'j', '8271', 'v', 'o', 'z', 'r', 'W', '6837', 'q', '4813', 'G', 'k', 'R', '1255', '503']

2831, 14, 24, 1349, 11, 10, 8271, 22, 15, 26, 18, 23, 6837, 17, 4813, 7, 11, 18, 1255, 503