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: 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: 8, 21, ['2381', '5057', 'o', 'M', '7495', '3787', '3877', '5055', '6055', '4145', 'v', 'O', 'K', '361', 'X', 'H', '357', 'H', '7553', 'S', 'R', 'H', '5973']

SOLUTION: RS3557H753HX163KOv541455065505

PROBLEM: 1, 3, ['7807', '3073', '2093', '8137', '8571', '2701', '9393', '2821', '9049', 'D', 's', 'i', 'v', '4207', '4639', 'N', '9867', '5771', '1437', '343', '5341', 'u', '3927', 'u', 'x', '8149', 'v']

SOLUTION:
390237037087