4 and 9 could be 1 array. 2 and 18 can be another array. 3 and 12 could be another one. 6 and 6 could be another array. Lastly, 1 and 36 could be an array. There should be a total of 5 arrays. If you include the 1 and 36 array, then it's 5, I'd you don't include it, then it's 4 arrays.