last
nil
0
last
cons
x
nil
x
last
cons
x
cons
y
xs
last
cons
y
xs
del
x
nil
nil
del
x
cons
y
xs
if
eq
x
y
x
y
xs
if
true
x
y
xs
xs
if
false
x
y
xs
cons
y
del
x
xs
eq
0
0
true
eq
0
s
y
false
eq
s
x
0
false
eq
s
x
s
y
eq
x
y
reverse
nil
nil
reverse
cons
x
xs
cons
last
cons
x
xs
reverse
del
last
cons
x
xs
cons
x
xs
2.2
reverse
cons
x
xs
reverse
del
last
cons
x
xs
cons
x
xs
if
false
x
y
xs
del
x
xs
last
cons
x
cons
y
xs
last
cons
y
xs
del
x
cons
y
xs
if
eq
x
y
x
y
xs
eq
s
x
s
y
eq
x
y
reverse
cons
x
xs
del
last
cons
x
xs
cons
x
xs
reverse
cons
x
xs
last
cons
x
xs
del
x
cons
y
xs
eq
x
y
reverse
cons
x
xs
last
cons
x
xs
true
reverse
cons
x
xs
reverse
del
last
cons
x
xs
cons
x
xs
true
Failed!
NaTT
certifiable-1.6