b
c
x1
a
x1
b
b
x1
a
c
x1
a
x1
c
b
x1
c
c
c
x1
b
x1
2.2
b
b
x1
c
x1
c
c
c
x1
b
x1
b
c
x1
a
x1
a
x1
c
b
x1
b
b
x1
a
c
x1
a
x1
b
x1
true
a
x1
b
x1
b
b
x1
a
c
x1
a
x1
c
b
x1
c
c
c
x1
b
x1
b
c
x1
a
x1
b
b
x1
c
x1
true
a
1
1
63723
b
1
1
42482
c
1
1
21241
c
1
1
0
a
1
1
42483
b
1
1
21243
c
c
c
x1
b
x1
b
c
x1
a
x1
a
x1
c
b
x1
b
b
x1
a
c
x1
NaTT
certifiable-1.6