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CF2162C.Beautiful XOR
Beautiful XOR
You are given two integers and . You are allowed to perform the following operation any number of times (including zero):
- choose any integer such that (the current value of , not initial),
- set . Here, represents the bitwise XOR operator.
After performing a sequence of operations, you want the value of to become exactly .
Find a sequence of at most operations (values of used in each operation) that transforms into , or report that it is impossible.
Note that you are not required to find the minimum number of operations, but any valid sequence of at most operations.
Input
The first line of input contains a single integer () — the number of test cases.
Each test case contains two integers and ().
Output
For each test case, if it is impossible to obtain from using the allowed operations, print a single line containing .
Otherwise, on the first line print a single integer () — the number of operations. On the second line print integers () — the chosen values of in the order you apply them.
If there are multiple valid sequences, you may print any one of them.
Note
For the first test case,
- choose , now becomes equal to .
- choose , now becomes equal to .
Thus, we can make .
For the fourth test case, choosing makes .
Samples
6
9 6
13 13
292 929
405 400
998 244
244 353
2
7 8
0
-1
1
5
2
25 779
-1
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