Teacher: 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.
Teacher: Now, understand the problem? If you are still confused, see the following example:
1, 3, ['238', 'h', '92', 'U', '2799']
Solution: 29h832
Reason: Here, concatenating all the elements between the 1st element and 3rd element and then reversing the string gives '29h832'.

Now, solve this instance: 6, 19, ['6125', '9069', '5411', '9593', 'v', 'Y', '8153', '7129', '2503', '1853', '4347', '3835', '7689', 'A', 'y', 'X', 'Z', '5269', 'R', 'Y', 'w', '2379', '8997', '4287', '2247', '2667', 'g', 'u', '1893']
Student:
R9625ZXyA9867538374343581305292173518Y