Definition: In this task, you are given inputs i,j, and A, where i and j are integers and A is a list. You need to concatenate all elements of A from the ith element to the jth element, and print the resultant 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.
Input: 18, 20, ['C', 'h', '8975', 'z', 'U', 'U', 'h', '4753', '6569', 's', '821', 'a', '7791', 'O', 'S', '3807', '1883', '427', 'd', '9817', 'F', '4733']

427d9817