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: 14, 20, ['9977', 't', 'Y', 'i', '7981', 'a', '1711', '3371', '9143', '3665', '1525', 'y', 'b', '379', 'k', 'T', 'Q', 'D', 'c', '1001', '551', 'Z']

SOLUTION: 1001cDQTk973

PROBLEM: 5, 5, ['m', '1577', '7895', 'l', 'K', '2981', '8677']

SOLUTION: K

PROBLEM: 12, 21, ['E', 'P', '41', 'o', '5953', 'P', '3671', 'l', '37', 'C', '7641', 't', '6143', 'L', 'S', 'N', '7723', '725', '8859', '483', 'u']

SOLUTION:
u38495885273277NSL3416t