3x+y+0( 15-x-y)=33，

3x+y=33，

y=33-3x

X and y are positive integers or 0, and x+y ≤15;

①x = 9y = 6；

15-9-6=0;

②x = 10y = 3；

15- 10-3=2;

③ x= 1 1 y=0。

15- 1 1-0=4;

There are three situations: ①9 wins, 6 draws and 0 losses; ② 10 wins, 3 draws and 2 losses; ③ 1 1 win, 0 draw and 4 losses.

So the answer is: 3.