How many clients from Mozambique required orders with a low priority order?
Mozambique refers to n_name = 'MOZAMBIQUE'; low priority order refers to o_orderpriority = '5-LOW'
SELECT COUNT(T1.c_custkey) FROM customer AS T1 INNER JOIN nation AS T2 ON T1.c_nationkey = T2.n_nationkey INNER JOIN orders AS T3 ON T1.c_custkey = T3.o_custkey WHERE T2.n_name = 'MOZAMBIQUE' AND T3.o_orderpriority = '5-LOW'