isLeaf
leaf
true
isLeaf
cons
u
v
false
left
cons
u
v
u
right
cons
u
v
v
concat
leaf
y
y
concat
cons
u
v
y
cons
u
concat
v
y
less_leaves
u
v
if1
isLeaf
u
isLeaf
v
u
v
if1
b
true
u
v
false
if1
b
false
u
v
if2
b
u
v
if2
true
u
v
true
if2
false
u
v
less_leaves
concat
left
u
right
u
concat
left
v
right
v
2.2
if1
b
false
u
v
if2
b
u
v
if2
false
u
v
right
u
if2
false
u
v
right
v
less_leaves
u
v
isLeaf
u
less_leaves
u
v
isLeaf
v
if2
false
u
v
concat
left
v
right
v
less_leaves
u
v
if1
isLeaf
u
isLeaf
v
u
v
if2
false
u
v
left
u
if2
false
u
v
less_leaves
concat
left
u
right
u
concat
left
v
right
v
concat
cons
u
v
y
concat
v
y
if2
false
u
v
left
v
if2
false
u
v
concat
left
u
right
u
true
if2
false
u
v
less_leaves
concat
left
u
right
u
concat
left
v
right
v
less_leaves
u
v
if1
isLeaf
u
isLeaf
v
u
v
if1
b
false
u
v
if2
b
u
v
true
Failed!
NaTT
certifiable-1.6