select count(*)
from (select distinct c_last_name, c_first_name, d_date
      from store_sales,
           date_dim,
           customer
      where store_sales.ss_sold_date_sk = date_dim.d_date_sk
        and store_sales.ss_customer_sk = customer.c_customer_sk
        and d_month_seq between 1200 and 1200 + 11
      intersect
      select distinct c_last_name, c_first_name, d_date
      from catalog_sales,
           date_dim,
           customer
      where catalog_sales.cs_sold_date_sk = date_dim.d_date_sk
        and catalog_sales.cs_bill_customer_sk = customer.c_customer_sk
        and d_month_seq between 1200 and 1200 + 11
      intersect
      select distinct c_last_name, c_first_name, d_date
      from web_sales,
           date_dim,
           customer
      where web_sales.ws_sold_date_sk = date_dim.d_date_sk
        and web_sales.ws_bill_customer_sk = customer.c_customer_sk
        and d_month_seq between 1200 and 1200 + 11) hot_cust limit 100