TASK 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.
PROBLEM: ['b', 'u', 'r', '3453', '1663', 'b', '651', 'R', 'U', 'U', 'a', 'b', '2769', 'C']

SOLUTION: 2, 21, 18, 3453, 1663, 2, 651, 18, 21, 21, 1, 2, 2769, 3

PROBLEM: ['B', '1491', 'Q', 'y', 'D', 'b', '1667', 'W', '9611', '3105', 'Z', '3705', '9391']

SOLUTION: 2, 1491, 17, 25, 4, 2, 1667, 23, 9611, 3105, 26, 3705, 9391

PROBLEM: ['6587', 'h', 'D', 'c', '3925', 'x', '5149', '2809', '8727', 'b', 'n', '6175', '1083', 'K', 'Z', '5489', '3097', '7113', '4913', 'L', 'q', '4265', '429', 'k', 'x', 't', 'i', 's', '7163', '6371', 'D']

SOLUTION:
6587, 8, 4, 3, 3925, 24, 5149, 2809, 8727, 2, 14, 6175, 1083, 11, 26, 5489, 3097, 7113, 4913, 12, 17, 4265, 429, 11, 24, 20, 9, 19, 7163, 6371, 4