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: 2, 21, ['K', '8135', 'c', '1937', '2469', '4531', '4285', '4939', '6607', 'x', 's', 'P', '8111', '8743', 'Y', '2967', 'h', '9605', '6795', 'z', 'W', 'a', '209']

8135c193724694531428549396607xsP81118743Y2967h96056795zW