c
a
a
b
c
c
a
a
b
c
x1
a
a
b
c
c
a
a
b
c
a
a
b
c
c
x1
2.2
c
a
a
b
c
c
a
a
b
c
x1
c
a
a
b
c
a
a
b
c
c
x1
c
a
a
b
c
c
a
a
b
c
x1
c
a
a
b
c
c
x1
c
a
a
b
c
c
a
a
b
c
x1
c
c
a
a
b
c
a
a
b
c
c
x1
c
a
a
b
c
c
a
a
b
c
x1
c
c
x1
true
c
a
a
b
c
c
a
a
b
c
x1
c
c
x1
c
a
a
b
c
c
a
a
b
c
x1
c
c
a
a
b
c
a
a
b
c
c
x1
c
a
a
b
c
c
a
a
b
c
x1
c
a
a
b
c
c
x1
c
a
a
b
c
c
a
a
b
c
x1
c
a
a
b
c
a
a
b
c
c
x1
true
Failed!
NaTT
certifiable-1.6