fib
0
0
fib
s
0
s
0
fib
s
s
x
+
fib
s
x
fib
x
+
x
0
x
+
x
s
y
s
+
x
y
2.2
fib
s
s
x
+
fib
s
x
fib
x
fib
s
s
x
fib
s
x
+
x
s
y
+
x
y
fib
s
s
x
fib
x
true
fib
s
s
x
fib
x
fib
s
s
x
fib
s
x
true
s
1
1
1
fib
1
0
0
0
0
+
2
0
fib
1
1
0
+
2
0
fib
s
s
x
+
fib
s
x
fib
x
false
+
x
s
y
+
x
y
true
s
1
1
1
fib
1
0
0
0
0
+
2
0
fib
1
0
+
2
2
0
NaTT
certifiable-1.6