- Time limit: 2.00 s
- Memory limit: 256 MB
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
- $1 \le t \le 10^5$
- $0\leq a, b\leq 2^{64}-1$
Input:
3
2 5
1 1
0 7
Output:
3
-
7
For example, in the first test case, $f(3)=((2\cdot3) \oplus 5) \bmod 2^{64}=3$.