This High School has the following numbers of athletes on four of its boys' sports teams:
41 football players; 15 basketball players; 21 baseball players; 32 wrestlers
No wrestler is also a basketball player. 9 boys play both football and baseball. 5 boys wrestle and play baseball.
12 boys wrestle and play football.
6 boys play basketball and football.
7 boys play basketball and baseball.
3 boys are on all of the teams except basketball. 4 boys are on all of the teams except wrestling.
How many boys are involved in these four sports?