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: 6, 12, ['F', '7431', 'o', 'U', 's', 'X', 'o', '2139', '6845', '3421', '2085', '7793', '8947', '2025', '6833', 'j']

77932085342168452139oX