sum
cons
s
n
x
cons
m
y
sum
cons
n
x
cons
s
m
y
sum
cons
0
x
y
sum
x
y
sum
nil
y
y
empty
nil
true
empty
cons
n
x
false
tail
nil
nil
tail
cons
n
x
x
head
cons
n
x
n
weight
x
if
empty
x
empty
tail
x
x
if
true
b
x
weight_undefined_error
if
false
b
x
if2
b
x
if2
true
x
head
x
if2
false
x
weight
sum
x
cons
0
tail
tail
x
2.2
if2
false
x
weight
sum
x
cons
0
tail
tail
x
weight
x
if
empty
x
empty
tail
x
x
weight
x
tail
x
if2
true
x
head
x
sum
cons
s
n
x
cons
m
y
sum
cons
n
x
cons
s
m
y
weight
x
empty
x
if
false
b
x
if2
b
x
if2
false
x
tail
x
if2
false
x
sum
x
cons
0
tail
tail
x
sum
cons
0
x
y
sum
x
y
weight
x
empty
tail
x
if2
false
x
tail
tail
x
true
weight
x
if
empty
x
empty
tail
x
x
if
false
b
x
if2
b
x
if2
false
x
weight
sum
x
cons
0
tail
tail
x
true
Failed!
NaTT
certifiable-1.6