The total number of copies is 17, 9 copies are 9 heads, 6 copies are 6 heads and 2 copies are 2 heads.
This is the grade of grade six.
decimal
1/2+ 1/3+ 1/9= 17/ 18
Three people just got 17 heads. Only by borrowing a person's head can you score points, and you still have to return what you borrowed to others.