from
X
cons
X
from
s
X
first
0
Z
nil
first
s
X
cons
Y
Z
cons
Y
first
X
Z
sel
0
cons
X
Z
X
sel
s
X
cons
Y
Z
sel
X
Z
from
1
cons
2
s
1
first
2
0
0
nil
0
sel
2
INNERMOST
./TRS/outermost/nontermin/CSR/Ex1_Luc02b.trs