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: 18, 18, ['O', '7845', 'f', '2313', 'f', '9661', 's', 'O', '6009', '6997', 'f', 'T', 'f', '6517', 'E', 'H', 'k', 'Y', 'i', '2839', '1839', '3251', 'H', '1939']

SOLUTION: Y

PROBLEM: 1, 4, ['B', '5591', '1237', '1519']

SOLUTION: 915173211955B

PROBLEM: 6, 8, ['t', 'z', '2173', 'E', '857', 'O', '3381', '3669', '1027', '3237', '537', 'h', '2537', 'M', '8333', '321', 'u', 'J', '4897', '5617', 'l', '3513', 'p']

SOLUTION:
96631833O