and
true
X
X
and
false
Y
false
if
true
X
Y
X
if
false
X
Y
Y
add
0
X
X
add
s
X
Y
s
add
X
Y
first
0
X
nil
first
s
X
cons
Y
Z
cons
Y
first
X
Z
from
X
cons
X
from
s
X
and
2
1
true
0
false
0
if
3
1
add
2
1
0
0
s
1
first
2
1
2
nil
0
cons
2
from
1
FULL
./TRS/CSR/Ex15_Luc98.trs