How can I get the max count in a Hive joined query

Question

I have this query:

select 

a.item_page_productid,
b.category_id,
a.viewcount

from 

(select 
item_page_productid,
count(*) as viewcount
from views 
where  eventdate > to_date(days_sub(now(), 60))
group by item_page_productid
) a

join

(select
 product_id,
 category_id
 from catalog_products_in_categories
 where active = 't') b

 on a.item_page_productid=b.category_id

What I am trying to do is pair a single item_page_productid with a single category_id with the item_page_productid paired being the one with the highest viewcount.

Any ideas?