cond
true
x
cond
and
even
x
gr
x
0
p
x
and
x
false
false
and
false
x
false
and
true
true
true
even
0
true
even
s
0
false
even
s
s
x
even
x
gr
0
x
false
gr
s
x
0
true
gr
s
x
s
y
gr
x
y
p
0
0
p
s
x
x
2.2
gr
s
x
s
y
gr
x
y
cond
true
x
gr
x
0
cond
true
x
p
x
cond
true
x
even
x
cond
true
x
cond
and
even
x
gr
x
0
p
x
even
s
s
x
even
x
cond
true
x
and
even
x
gr
x
0
true
cond
true
x
cond
and
even
x
gr
x
0
p
x
true
Failed!
NaTT
certifiable-1.6