t
f
x1
t
c
n
x1
n
f
x1
f
n
x1
o
f
x1
f
o
x1
n
s
x1
f
s
x1
o
s
x1
f
s
x1
c
f
x1
f
c
x1
c
n
x1
n
c
x1
c
o
x1
o
c
x1
c
o
x1
o
x1
2.2
c
f
x1
c
x1
t
f
x1
t
c
n
x1
c
o
x1
o
c
x1
t
f
x1
c
n
x1
c
o
x1
c
x1
o
f
x1
o
x1
c
n
x1
n
c
x1
n
f
x1
n
x1
t
f
x1
n
x1
c
n
x1
c
x1
true
t
f
x1
t
c
n
x1
true
Failed!
NaTT
certifiable-1.6