a__first
0
X
nil
a__first
s
X
cons
Y
Z
cons
mark
Y
first
X
Z
a__from
X
cons
mark
X
from
s
X
mark
first
X1
X2
a__first
mark
X1
mark
X2
mark
from
X
a__from
mark
X
mark
0
0
mark
nil
nil
mark
s
X
s
mark
X
mark
cons
X1
X2
cons
mark
X1
X2
a__first
X1
X2
first
X1
X2
a__from
X
from
X
a__first
2
0
0
nil
0
s
1
cons
2
mark
1
first
2
a__from
1
from
1
FULL
./TRS/TRCSR/Ex6_Luc98_GM.trs