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