b
c
a
x1
a
b
x1
b
b
b
x1
c
a
c
x1
c
d
x1
d
c
x1
c
d
b
x1
d
c
c
x1
d
c
x1
b
b
b
x1
c
b
x1
d
a
x1
d
b
c
x1
a
a
x1
d
a
x1
b
x1
2.2
b
b
b
x1
c
x1
d
c
x1
b
x1
c
d
b
x1
c
x1
b
c
a
x1
b
x1
c
d
b
x1
d
c
c
x1
c
d
b
x1
c
c
x1
c
d
x1
d
c
x1
d
a
x1
b
x1
d
c
x1
b
b
x1
c
b
x1
d
a
x1
b
b
b
x1
c
a
c
x1
c
d
x1
c
x1
d
c
x1
b
b
b
x1
true
d
c
x1
b
b
b
x1
c
d
b
x1
c
c
x1
c
d
x1
c
x1
c
b
x1
d
a
x1
c
d
b
x1
d
c
c
x1
b
c
a
x1
b
x1
c
d
b
x1
c
x1
d
c
x1
b
x1
d
c
x1
b
b
x1
d
a
x1
b
x1
c
d
x1
d
c
x1
b
b
b
x1
c
x1
true
a
1
1
0
d
1
1
61230
b
1
1
30615
c
1
1
30615
d
1
1
30617
c
1
1
4
b
1
1
0
c
d
b
x1
d
c
c
x1
d
a
x1
b
x1
b
c
a
x1
a
b
x1
c
d
x1
d
c
x1
d
c
x1
b
b
b
x1
d
b
c
x1
a
a
x1
c
b
x1
d
a
x1
b
b
b
x1
c
a
c
x1
b
b
b
x1
c
a
c
x1
false
NaTT
certifiable-1.6