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
from
1
1
cons
2
1
s
1
1
head
1
1
2nd
1
1
take
2
1
2
0
0
nil
0
sel
2
1
2
FULL
./TRS/CSR/Ex7_BLR02.trs