app
app
app
fold
f
nil
x
x
app
app
app
fold
f
app
app
cons
h
t
x
app
app
app
fold
f
t
app
app
f
x
h
app
sum
l
app
app
app
fold
add
l
0
app
app
app
fold
mul
l
1
app
prod
l
app
2
fold
0
nil
0
cons
0
sum
0
add
0
0
0
mul
0
1
0
prod
0
FULL
./TRS/higher-order/Lifantsev/Ex6Folding.trs