The paint department has been given thear assignment of designing color codes for 42 different parts. There are a total of seven colors available. Three colors are to be used on each part. A combination of three colors used for one part cannot be rearranged and used to identify a different part. This means that if green, yellow, and red were used to identify a cam shaft, red, green and yellow (or any combination of these three colors) could not be used to identify another part. How many parts can the paint department code?