Definition: 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.
Input: 14, 21, ['3829', 'b', 'U', 'f', '4939', 'k', '7855', 'm', '6179', '7031', '3177', 'T', 'G', 't', '5265', 'L', '245', '2387', '2039', '5281', '3903', '8701']

3903528120392387245L5265t