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, 5, ['7115', '3109', '3805', '6831', '6897', 'y', 'b']

SOLUTION: 79861386508390135117

PROBLEM: 6, 7, ['2289', '1015', 'T', 'e', '4499', 'J', 'B', '5107', 'x', '3103', 'Q', 'Z', 'H']

SOLUTION: BJ

PROBLEM: 7, 8, ['8477', 'f', 'A', 'v', 'f', 'U', '7967', 'L', '3371']

SOLUTION:
L7697