a
b
b
x1
P
a
b
x1
a
P
x1
P
a
x
x1
a
x
x1
x
a
x1
b
P
x1
b
Q
x1
Q
x
x1
a
Q
x1
Q
a
x1
b
b
a
x1
2.2
Q
a
x1
b
b
a
x1
a
x
x1
a
x1
b
P
x1
Q
x1
a
b
b
x1
a
b
x1
Q
x
x1
Q
x1
Q
a
x1
b
a
x1
a
P
x1
a
x
x1
b
P
x1
b
Q
x1
Q
x
x1
a
Q
x1
true
b
P
x1
b
Q
x1
Q
a
x1
b
a
x1
b
P
x1
Q
x1
Q
x
x1
Q
x1
Q
a
x1
b
b
a
x1
true
a
1
21241
Q
1
21241
b
1
1
Q
1
21241
x
1
21241
P
1
21241
a
1
0
b
1
1
0
Q
x
x1
Q
x1
b
P
x1
Q
x1
Q
a
x1
b
a
x1
b
P
x1
b
Q
x1
b
P
x1
b
Q
x1
a
b
b
x1
P
a
b
x1
a
x
x1
x
a
x1
Q
x
x1
a
Q
x1
Q
a
x1
b
b
a
x1
a
P
x1
P
a
x
x1
b
P
x1
Q
x1
b
P
x1
b
Q
x1
Q
x
x1
Q
x1
Q
a
x1
b
a
x1
true
Failed!
NaTT
certifiable-1.6