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:
1, 7, ['P', 'h', '1443', 'b', 'K', '2641', '3831']
answer:
13831462Kb3441hP


question:
13, 15, ['L', 'A', '2959', 'g', '7157', '9131', 'o', 'D', 'q', 'd', 'A', '4249', 'K', 'U', '4805', 'h', '7981']
answer:
5084UK


question:
3, 7, ['s', 'k', '2781', '6551', '8745', 'D', '2437', 'R', 'a', '173', 'v', '1801', '5783', 'c', 'F', '9875', 'X', 'H', '3799', '8635', '5319']
answer:

7342D547815561872