Write SQL query to solve given problem: Among the suppliers providing parts under the type "promo brushed steel", how many of them are in debt?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT COUNT(T3.s_name) FROM part AS T1 INNER JOIN partsupp AS T2 ON T1.p_partkey = T2.ps_partkey INNER JOIN supplier AS T3 ON T2.ps_suppkey = T3.s_suppkey WHERE T3.s_acctbal < 0 AND T1.p_type = 'PROMO BRUSHED STEEL'