A construction company uses regular and dually trucks (trucks that have 2 tires in the back on each side, so have 6 tires total). Altogether they have 73 trucks. They are planning to replace the tires on all their vehicles and have ordered 354 tires. If the regular trucks have 4 tires each and the dually's have 6 tires each, how many of each type of truck do they own?