instruction:
In this task, you are given inputs i, j, and A, where i and j are integers and A is a list. You need to find all elements of A from the ith element to the jth element, reverse the order in which they occur, and then concatenate them to output the resultant 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 concatenate the elements and then reverse the string.
question:
3, 3, ['U', '8399', '645', '3165']
answer:
645


question:
3, 3, ['2789', '6611', '5143']
answer:
5143


question:
4, 4, ['4623', 'J', 'k', '5579', 'X']
answer:

5579