select count(*) 
from (select distinct c_last_name as l1, c_first_name as f1, d_date as d1
       from store_sales
        JOIN date_dim ON store_sales.ss_sold_date_sk = date_dim.d_date_sk
        JOIN customer ON store_sales.ss_customer_sk = customer.c_customer_sk
       where 
         d_month_seq between 1193 and 1193+11
         and ss_sold_date between '1999-06-01' and '2000-05-31'
	) t1
      LEFT OUTER JOIN
      ( select distinct c_last_name as l2, c_first_name as f2, d_date as d2
       from catalog_sales
        JOIN date_dim ON catalog_sales.cs_sold_date_sk = date_dim.d_date_sk
        JOIN customer ON catalog_sales.cs_bill_customer_sk = customer.c_customer_sk
       where 
         d_month_seq between 1193 and 1193+11
         and cs_sold_date between '1999-06-01' and '2000-05-31'
	) t2
      ON t1.l1 = t2.l2 and
       t1.f1 = t2.f2 and
       t1.d1 = t2.d2
      LEFT OUTER JOIN
      (select distinct c_last_name as l3, c_first_name as f3, d_date as d3
       from web_sales
        JOIN date_dim ON web_sales.ws_sold_date_sk = date_dim.d_date_sk
        JOIN customer ON web_sales.ws_bill_customer_sk = customer.c_customer_sk
       where 
         d_month_seq between 1193 and 1193+11
         and ws_sold_date between '1999-06-01' and '2000-05-31'
	) t3
      ON t1.l1 = t3.l3 and
       t1.f1 = t3.f3 and
       t1.d1 = t3.d3
WHERE
    l2 is null and
    l3 is null ;