from
X
cons
X
from
s
X
head
cons
X
XS
X
2nd
cons
X
XS
head
XS
take
0
XS
nil
take
s
N
cons
X
XS
cons
X
take
N
XS
sel
0
cons
X
XS
X
sel
s
N
cons
X
XS
sel
N
XS
2.2
take
s
N
cons
X
XS
take
N
XS
2nd
cons
X
XS
head
XS
sel
s
N
cons
X
XS
sel
N
XS
from
X
from
s
X
true
from
X
from
s
X
true
Failed!
NaTT
certifiable-1.6