Among the suppliers from Middle East region, how many suppliers were in debt?
suppliers from Middle East region refer to s_name where r_name = 'MIDDLE EAST'; in debt refers to s_acctbal < 0;
SELECT COUNT(T3.s_name) FROM region AS T1 INNER JOIN nation AS T2 ON T1.r_regionkey = T2.n_regionkey INNER JOIN supplier AS T3 ON T2.n_nationkey = T3.s_nationkey WHERE T3.s_acctbal < 0 AND T1.r_name = 'MIDDLE EAST'