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: 19, 20, ['3457', 'R', 'O', '1711', 'E', '5843', '9027', '2515', '2887', '2165', 'C', 'p', '1933', '5139', '6285', '2207', '9159', '4087', 'L', '3439', 'd', '1603', 'Z']

3439L