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: 17, 21, ['173', 'u', '4103', 'g', 'U', '7753', 'H', '5271', 'T', '9339', 'r', 'U', '7277', '1555', '7647', '2063', 'U', 'P', '409', '3777', '1605', 'L', 'o', '7659', '1819', 'f', '9129', 'x', 'l']

16053777409PU