1-1=0
2-1=1 2-2=0
3-1=1 3-2=1 3-3=0
4-1=3 4-2=2 4-3=1 4-4=0
5-1=4 5-2=3 5-3=2 5-4=1 5-5=0
6-1=5 6-2=4 6-3=3 6-4=2 6-5=1 6-6=0
1-1=0
2-1=1 2-2=0
3-1=1 3-2=1 3-3=0
4-1=3 4-2=2 4-3=1 4-4=0
5-1=4 5-2=3 5-3=2 5-4=1 5-5=0
6-1=5 6-2=4 6-3=3 6-4=2 6-5=1 6-6=0