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: 11, 20, ['T', 'U', '8683', 'N', 'X', 'F', '1307', 'Y', '1347', '6855', 'Y', '2007', '8981', '1943', 'F', '5463', '9905', 'L', '3509', '5787', 'b']

57873509L99055463F194389812007Y