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: 1, 21, ['X', '8417', 'F', 'n', '2015', '7307', '4551', 'v', 'c', '815', 'k', 'h', 'r', '557', 'l', '3381', 'p', 'z', 'U', '5271', '7299', '6709']

X8417Fn201573074551vc815khr557l3381pzU52717299