op
F
G
X
F
G
X
implode
nil
F
X
X
implode
cons
H
T
F
X
implode
T
F
F
X
explode
nil
F
X
X
explode
cons
H
T
F
X
explode
T
op
F
F
F
X
F
nat
nat
G
nat
nat
H
nat
T
list
X
nat
nil
list
cons
nat
list
list
op
nat
nat
nat
nat
nat
nat
implode
list
nat
nat
nat
nat
explode
list
nat
nat
nat
nat
FULL
.