CREATE TABLE table_19706 ("Prefix size" TEXT, "Network mask" TEXT, "Available subnets" FLOAT, "Usable hosts per subnet" FLOAT, "Total usable hosts" FLOAT)

When the network mask is 255.255.255.224 what is the highest total usable host?
SELECT MAX("Total usable hosts") FROM table_19706 WHERE "Network mask" = '255.255.255.224'
SELECT MAX("Total usable hosts") FROM "table_19706" WHERE "Network mask" = '255.255.255.224'