lt
0
s
x
true
lt
x
0
false
lt
s
x
s
y
lt
x
y
fac
x
help
x
0
help
x
c
if
lt
c
x
x
c
if
true
x
c
times
s
c
help
x
s
c
if
false
x
c
s
0
2.2
help
x
c
if
lt
c
x
x
c
fac
x
help
x
0
help
x
c
lt
c
x
if
true
x
c
help
x
s
c
lt
s
x
s
y
lt
x
y
true
fac
x
help
x
0
false
if
true
x
c
help
x
s
c
help
x
c
if
lt
c
x
x
c
true
Failed!
NaTT
certifiable-1.6