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, 12, ['f', '8665', '6205', 'L', 'y', 'P', '9351', 'k', '1387', '657', 's', 'k']
answer:
ks7567831k1539PyL50265668f


question:
2, 5, ['Y', 'O', 'Q', 'l', 'E']
answer:
ElQO


question:
3, 4, ['3531', 'F', '5197', '2843']
answer:

34827915