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: 6, 13, ['a', 't', '3699', 'H', 'c', 'S', '2713', '5419', 'q', '7877', 'q', 'U', '833', '8411', '2003', '5373', 'P', '2913']

SOLUTION: 338Uq7787q91453172S

PROBLEM: 16, 18, ['7121', 'b', 'P', '7771', 'l', 'I', '7817', '5185', '7989', 'H', '4449', '3859', '869', '9321', 'O', '6453', '6219', '8349', '5327', 'm', 'c', 'O', '1185', '2703', '9673', 'q']

SOLUTION: 943891263546

PROBLEM: 5, 7, ['433', 'G', '7265', 'p', 's', '3521', '9751']

SOLUTION:
15791253s