lt
0
s
x
true
lt
x
0
false
lt
s
x
s
y
lt
x
y
fibo
0
fib
0
fibo
s
0
fib
s
0
fibo
s
s
x
sum
fibo
s
x
fibo
x
fib
0
s
0
fib
s
0
s
0
fib
s
s
x
if
true
0
s
s
x
0
0
if
true
c
s
s
x
a
b
if
lt
s
c
s
s
x
s
c
s
s
x
b
c
if
false
c
s
s
x
a
b
sum
fibo
a
fibo
b
sum
x
0
x
sum
x
s
y
s
sum
x
y
2.2
fibo
s
s
x
fibo
s
x
if
false
c
s
s
x
a
b
sum
fibo
a
fibo
b
fibo
0
fib
0
if
true
c
s
s
x
a
b
if
lt
s
c
s
s
x
s
c
s
s
x
b
c
fibo
s
0
fib
s
0
lt
s
x
s
y
lt
x
y
if
false
c
s
s
x
a
b
fibo
a
if
true
c
s
s
x
a
b
lt
s
c
s
s
x
fib
s
s
x
if
true
0
s
s
x
0
0
fibo
s
s
x
fibo
x
fibo
s
s
x
sum
fibo
s
x
fibo
x
if
false
c
s
s
x
a
b
fibo
b
sum
x
s
y
sum
x
y
true
fib
s
s
x
if
true
0
s
s
x
0
0
false
if
true
c
s
s
x
a
b
if
lt
s
c
s
s
x
s
c
s
s
x
b
c
true
Failed!
NaTT
certifiable-1.6