f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
2.2
f
f
f
a
x
b
b
f
a
f
f
x
b
b
f
a
f
a
f
a
f
x
b
f
a
f
a
f
a
x
f
a
f
a
f
a
f
x
b
f
a
f
a
x
f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
f
f
a
x
b
b
f
f
x
b
b
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
f
a
f
a
f
a
f
x
b
f
a
x
f
f
f
a
x
b
b
f
x
b
true
f
f
f
a
x
b
b
f
x
b
f
a
f
a
f
a
f
x
b
f
a
x
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
f
f
f
a
x
b
b
f
f
x
b
b
f
a
f
a
f
a
f
x
b
f
a
f
a
f
a
x
f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
a
f
a
f
a
f
x
b
f
a
f
a
x
f
f
f
a
x
b
b
f
a
f
f
x
b
b
true
a
0
7720
b
0
0
f
2
1
2
0
f
2
1
2
0
f
f
f
a
x
b
b
f
a
f
f
x
b
b
f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
a
f
a
f
a
f
x
b
f
a
f
a
f
a
x
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
f
a
f
a
f
a
f
x
b
f
a
f
a
f
a
x
f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
f
f
a
x
b
b
f
a
f
f
x
b
b
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
true
2
1
a
0
19692
0
b
0
1
19694
f
2
0
1
0
0
1
1
1
f
2
1
0
0
0
1
1
1
1
0
2
0
0
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
f
a
f
a
f
a
f
x
b
f
a
f
a
f
a
x
f
a
f
a
f
a
f
x
b
f
f
a
f
a
f
a
x
b
f
f
f
a
x
b
b
f
f
a
f
f
x
b
b
b
f
a
f
a
f
a
f
x
b
f
a
f
a
f
a
x
true
Failed!
NaTT
certifiable-1.6