a
a
x1
b
b
b
c
x1
b
c
b
x1
a
b
c
x1
2.2
b
c
b
x1
b
c
x1
a
a
x1
b
c
x1
a
a
x1
b
b
b
c
x1
b
c
b
x1
a
b
c
x1
a
a
x1
b
b
c
x1
true
a
a
x1
b
b
c
x1
b
c
b
x1
a
b
c
x1
a
a
x1
b
b
b
c
x1
a
a
x1
b
c
x1
b
c
b
x1
b
c
x1
true
a
1
2438
b
1
2438
c
1
2439
a
1
1
1
b
1
1
0
b
c
b
x1
b
c
x1
a
a
x1
b
c
x1
b
c
b
x1
a
b
c
x1
a
a
x1
b
b
b
c
x1
b
c
b
x1
a
b
c
x1
a
a
x1
b
c
x1
b
c
b
x1
b
c
x1
b
c
b
x1
a
b
c
x1
true
Failed!
NaTT
certifiable-1.6