1st cn
0+1
0+2
0+3
2nd cn
1
1-1
=1=
1+1
1+2
1+3
1
2-2
2-1
=2=
2+1
2+2
1
3-3
3-2
3-1
=3=
3+1
1
3rd cn
4-3
4-2
4-1
4th cn
1