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: 12, 20, ['4367', 'U', 'y', 'n', 'x', '4847', '2509', '2041', '4725', 'n', '63', 'g', '4881', 'p', 'u', 'i', 'l', 'f', '6829', 'f', '7435', 'l', '1845', '8923']

f6829fliup4881g