Among all the customers in Brazil, how many of them have an account balance of less than 1000?
customers refer to c_custkey; Brazil is the name of the nation which refers to n_name = 'BRAZIL'; account balance of less than 1000 refers to c_acctbal < 1000;
SELECT COUNT(T1.c_custkey) FROM customer AS T1 INNER JOIN nation AS T2 ON T1.c_nationkey = T2.n_nationkey WHERE T2.n_name = 'BRAZIL' AND T1.c_acctbal < 1000