Fixed points 
Time limit:  2.00 s 
Memory limit:  256 MB 

A fixed point for a function $f$ is a value $x$ such that $f(x)=x$.
In this task we focus on the following function:
$$ f(x) = ((a \cdot x) \oplus b) \bmod 2^{64}$$The operator $\oplus$ is the xor operator (written
^
in C++/Java).
Given $a$ and $b$, can you find a fixed point for the function?
Input
The first input line contains an integer $t$: the number of test cases.
After this, there are $t$ lines that describe the test cases. Each line contains two integers $a$ and $b$.
All test cases have been generated so that $a$ and $b$ have been chosen uniformly randomly from the range $0 \ldots 2^{64}1$.
Output
For each case, output a number $0\leq x\leq 2^{64}1$ that is a fixed point for the function, or "" if no such number exists.
If there are several possible solutions, you can output any of them.
Constraints
 $1 \le t \le 10^5$
 $0\leq a, b\leq 2^{64}1$
Example
Input:
3
2 5
1 1
0 7
Output:
3

7
For example, in the first test case, $f(3)=((2\cdot3) \oplus 5) \bmod 2^{64}=3$.