+
x
0
x
+
0
x
x
+
s
x
s
y
s
s
+
x
y
+
+
x
y
z
+
x
+
y
z
*
x
0
0
*
0
x
0
*
s
x
s
y
s
+
*
x
y
+
x
y
*
*
x
y
z
*
x
*
y
z
app
nil
l
l
app
cons
x
l1
l2
cons
x
app
l1
l2
sum
nil
0
sum
cons
x
l
+
x
sum
l
sum
app
l1
l2
+
sum
l1
sum
l2
prod
nil
s
0
prod
cons
x
l
*
x
prod
l
prod
app
l1
l2
*
prod
l1
prod
l2
+
2
0
0
s
1
*
2
app
2
nil
0
cons
2
sum
1
prod
1
FULL
./TRS/Cime/list-sum-prod-assoc-append.trs