plus
0
x
x
plus
s
x
y
s
plus
p
s
x
y
times
0
y
0
times
s
x
y
plus
y
times
p
s
x
y
p
s
0
0
p
s
s
x
s
p
s
x
fac
0
x
x
fac
s
x
y
fac
p
s
x
times
s
x
y
factorial
x
fac
x
s
0
plus
2
0
0
s
1
p
1
times
2
fac
2
factorial
1
INNERMOST
./TRS/Thiemann/factorial1.trs