Considering a disk with a number of tracks and each track has multiple sectors, we have a notation of a disk visit as (a, b), where a is the disk track number and b is the sector number on track a. For the following sequence of requests: (1, 23), (2, 57), (1,1), (1, 89), (2, 13), (2,78), (1,5), (2,75), (3, 45), (3,98), (2,72), (3,47), (2,76), (3,97). If you know this set of requests in advance, how would you reorder the sequence to minimize the total disk access time?