Radio Survey Problem ( Mathematical Ideas  by Miller, Hereen and Hornsby)

	It was found that Country-Western songs emphasize three basic 
themes: love, prison, and trucks. A survey of the local Country-Western 
radio station produced the following data:

12 songs about a truck driver who is		
     in love while in prison			
13 about a prisoner in love			
28 about a person in love			   
18 about a truck driver in love		   
 3 about a truck driver in prison		
    who is not in love				 
2 about people in prison who are not
  in love and do not drive trucks.
8 about people who are out of prison,
 are not in love, and do not drive a truck
16 about truck drivers who are not in prison
 

How many songs were surveyed?