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: 6, 21, ['F', '2689', 'u', 's', '6993', '6635', '2395', '1655', '8343', 'q', 'f', 'k', '6503', 't', 's', 'z', 'a', '4767', 'q', '139', 'E', 'e', '3109', '4273', '5099']

6635239516558343qfk6503tsza4767q139E