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, ['F', '6899', 'D', '4183', '5481', '4611', '6263', '1771', '3009', '89', 'K', 'q', '2963', 'y', '7893', '5009', '3109', 'u', '1933', '4635', '6643', 'C']

6899D41835481461162631771300989Kq2963y789350093109u193346356643