concat
leaf
Y
Y
concat
cons
U
V
Y
cons
U
concat
V
Y
lessleaves
X
leaf
false
lessleaves
leaf
cons
W
Z
true
lessleaves
cons
U
V
cons
W
Z
lessleaves
concat
U
V
concat
W
Z
2.2
lessleaves
cons
U
V
cons
W
Z
lessleaves
concat
U
V
concat
W
Z
lessleaves
cons
U
V
cons
W
Z
concat
U
V
concat
cons
U
V
Y
concat
V
Y
lessleaves
cons
U
V
cons
W
Z
concat
W
Z
true
lessleaves
cons
U
V
cons
W
Z
lessleaves
concat
U
V
concat
W
Z
true
concat
2
0
false
0
0
lessleaves
2
1
2
0
true
0
0
concat
2
1
2
1
cons
2
1
2
2
lessleaves
2
0
leaf
0
20163
concat
leaf
Y
Y
concat
cons
U
V
Y
cons
U
concat
V
Y
lessleaves
cons
U
V
cons
W
Z
concat
U
V
false
lessleaves
cons
U
V
cons
W
Z
concat
W
Z
false
concat
cons
U
V
Y
concat
V
Y
true
concat
2
1
0
false
0
0
lessleaves
2
1
2
0
true
0
0
concat
2
1
2
1
cons
2
1
2
2
lessleaves
2
0
leaf
0
42736
concat
leaf
Y
Y
concat
cons
U
V
Y
cons
U
concat
V
Y
NaTT
certifiable-1.6