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, 12, ['W', '7747', '1915', 'Z', '6841', 'U', '7357', 'B', '5029', 'd', '69', 'E']

U7357B5029d69E