CREATE TABLE table_149426_4 (total_usable_hosts INT, network_mask VARCHAR)

When the network mask is 255.255.255.224 what is the highest total usable host?
SELECT MAX(total_usable_hosts) FROM table_149426_4 WHERE network_mask = "255.255.255.224"
SELECT MAX("total_usable_hosts") FROM "table_149426_4" WHERE "255.255.255.224" = "network_mask"