A
B
C
y1
x1
1
1
1
0
x1
1
1
1
0
1
0
x3
x3
1
0
1
0
y1
0
x1
2
y2
1
0
x2
x2
D
1
0
x1
y2
1
0
2
0
x2
1
0
x2
1
0
x3
1
0
x3
1
0
3
3
4
4
5
5
A
B
C
D