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: 3, 19, ['4985', '7681', 'm', 'W', 'd', 'T', 'r', '4267', '8779', '7709', 'c', '3963', 'X', 'y', '9587', '9435', '6101', '4999', 'b']

b4999610194359587yX3963c770987794267rTdWm