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, 2, ['5111', 'U', '441', '8381']
answer:
U1115


question:
3, 3, ['2047', 'R', '6885', '1243', 'Z']
answer:
5886


question:
1, 2, ['8115', '7209']
answer:

90275118