b
d
b
x1
c
d
b
x1
b
a
c
x1
b
c
x1
a
d
x1
d
c
x1
b
b
b
x1
a
b
c
x1
d
c
x1
b
d
x1
d
c
x1
d
b
d
x1
d
a
c
x1
b
b
x1
2.2
d
c
x1
d
b
d
x1
d
a
c
x1
b
x1
a
d
x1
d
c
x1
b
b
b
x1
b
c
x1
d
c
x1
b
d
x1
b
b
b
x1
a
b
c
x1
d
a
c
x1
b
b
x1
d
c
x1
b
d
x1
b
a
c
x1
b
c
x1
d
c
x1
d
x1
d
c
x1
d
x1
true
a
d
x1
d
c
x1
false
d
c
x1
d
x1
d
c
x1
d
x1
d
c
x1
d
b
d
x1
true
a
1
1
1
d
1
1
0
b
1
1
1
c
1
1
1
d
1
1
0
a
1
0
b
1
0
d
c
x1
d
b
d
x1
b
b
b
x1
a
b
c
x1
b
d
b
x1
c
d
b
x1
a
d
x1
d
c
x1
d
c
x1
b
d
x1
d
a
c
x1
b
b
x1
d
c
x1
d
b
d
x1
b
a
c
x1
b
c
x1
d
c
x1
d
b
d
x1
true
Failed!
NaTT
certifiable-1.6