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: 11, 21, ['Y', 't', 'E', 'f', 'f', '349', 'y', '9137', '3139', '2223', '1609', 'C', '2717', 'b', '677', 't', '9693', 'W', '1587', 'r', 'U']

1609C2717b677t9693W1587rU