In this task, you are given inputs 'i', 'j', and A, where 'i' and 'j' are integers and A is a list. A list is shown by two brackets and comma-separated numbers and characters inside, like ['1', '12', 'l']. You need to concatenate all elements of A from the ith element to the jth element, and then reverse the resulting 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 reverse first and then concatenate.
14, 20, ['U', 't', 's', '3799', '2105', 'F', '5031', '8097', '9493', '3229', '7161', '6315', '5567', '6783', 'p', 'B', '3443', '8861', 's', 'B', '5201', '9873', 'b']