instruction:
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.
question:
3, 7, ['u', '1307', 'F', '8027', 'r', '4559', 'F', 'm', '9805', '5063']
answer:
F9554r7208F


question:
6, 7, ['753', '4657', 'h', '13', '593', 'I', '7689', '717']
answer:
9867I


question:
16, 21, ['3153', '517', '1831', '8333', '1959', '4231', 'M', 'a', 't', '1207', '6699', '3917', '1903', 'S', 'z', 'I', '317', '6541', 'k', 'L', 'F', '5611', 'z', '7325', 'W', '1715', '3051']
answer:

FLk1456713I