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: 21, 30, ['6469', '8717', 'L', 'X', '4715', '7595', '6757', '2935', 'B', '5035', 'j', 'X', '4897', '7607', '1621', '8217', 'd', 't', '183', 'm', '6453', 'M', '8871', 'l', '9347', 'P', '9341', 's', 'm', 'U']

Ums9341P9347l8871M6453