CREATE TABLE table_4937 ("Name" TEXT, "Vertices V" FLOAT, "Edges E" FLOAT, "Faces F" FLOAT, "Euler characteristic: V \\u2212 E + F" FLOAT)

What is the lowest Euler characteristic: V-E+F of a hexahedron or cube, which has less than 20 faces F, less than 30 edges E, and less than 8 vertices V?
SELECT MIN("Euler characteristic: V \u2212 E + F") FROM table_4937 WHERE "Faces F" < '20' AND "Edges E" < '30' AND "Name" = 'hexahedron or cube' AND "Vertices V" < '8'
SELECT MIN("Euler characteristic: V \u2212 E + F") FROM "table_4937" WHERE "Edges E" < '30' AND "Faces F" < '20' AND "Name" = 'hexahedron or cube' AND "Vertices V" < '8'