b
c
a
x1
a
b
a
b
x1
b
x1
c
c
x1
a
a
x1
a
c
b
a
x1
2.2
a
a
x1
b
a
x1
b
c
a
x1
b
x1
b
c
a
x1
a
b
x1
b
c
a
x1
a
b
a
b
x1
a
a
x1
a
c
b
a
x1
b
c
a
x1
b
a
b
x1
true
b
c
a
x1
b
a
b
x1
b
c
a
x1
a
b
a
b
x1
b
c
a
x1
b
x1
b
c
a
x1
a
b
x1
a
a
x1
b
a
x1
true
2
1
a
1
0
1
1
0
1
26389
0
b
1
0
0
1
1
1
0
0
c
1
0
1
0
0
1
0
0
a
1
0
0
1
0
1
1
0
b
1
0
0
1
0
1
0
0
b
c
a
x1
a
b
a
b
x1
a
a
x1
a
c
b
a
x1
b
x1
c
c
x1
a
a
x1
a
c
b
a
x1
false
NaTT
certifiable-1.6