TASK DEFINITION: In this task, you are given inputs 'i', 'j', and A, where 'i' and 'j' are integers and A is a list. A list is shown by two brackets and comma-separated numbers and characters inside, like ['1', '12', 'l']. You need to concatenate all elements of A from the ith element to the jth element, and then reverse the resulting string. 'i' and 'j' will be non-negative, and will always have a value less than the length of A. 'i' will always be less than 'j'. Perform the operations in order, i.e., do not reverse first and then concatenate.
PROBLEM: 1, 2, ['Q', '6249', 'm', 'H', 'x', 'b', 'Z', 'z', '15']

SOLUTION: 9426Q

PROBLEM: 3, 10, ['s', '3299', 'K', 'D', '4621', '9075', 'K', '6987', 'S', '9829', 'm', 'I', '3797']

SOLUTION: 9289S7896K57091264DK

PROBLEM: 20, 23, ['H', '8481', 'K', 'Q', 'Z', 'P', 'e', '8003', '6127', 'x', '4501', '5141', '6805', 'w', 'c', '4865', 'R', '897', 'N', 'm', 'y', 'Z', '6095', 'o', 'I', 'n', '2637', 'f', 'E']

SOLUTION:
5906Zym