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, 21, ['A', 'O', '105', '4059', '1855', 'i', '6213', '3693', 'F', '891', '1991', 'o', 'u', 'C', 'g', 'U', 'c', '2149', '3979', 'B', 'S', '1069', 'p']

21493979BS