12
0         	15 15 15
1        	 0 15 15 
3        	15 12 11
4        	 9  9 13
6        	 4  4 12
7        	10  6  1
10        	 0  0  3
11        	15 15  0
12        	 8 15  1
13        	 8  0  0
14        	15  8  9
15        	 0  0  0