C. Serval and The Formulatime limit per test2 secondsmemory limit per test256 megabytesinputstandard inputoutputstandard output You are given two positive integers $$$x$$$ and $$$y$$$ ($$$1\le x, y\le 10^9$$$).Find a non-negative integer $$$k\le 10^{18}$$$, such that $$$(x+k) + (y+k) = (x+k)\oplus (y+k)$$$ holds$$$^{\text{∗}}$$$, or determine that such an integer does not exist.$$$^{\text{∗}}$$$$$$\oplus$$$ denotes the bitwise XOR operation. InputEach test contains multiple test cases. The first line contains the number of test cases $$$t$$$ ($$$1 \le t \le 10^4$$$). The description of the test cases follows. The only line of each test case contains two integers $$$x$$$ and $$$y$$$ ($$$1\le x, y\le 10^9$$$) — the given integers.OutputFor each test case, output a single integer $$$k$$$ ($$$0\le k\le 10^{18}$$$) — the integer you found. Print $$$-1$$$ if it is impossible to find such an integer.If there are multiple answers, you may print any of them.ExampleInput52 56 619 101024 40961198372 599188Output0
-1
1
1024
28
NoteIn the first test case, since $$$(2 + 0) + (5 + 0) = (2 + 0) \oplus (5 + 0) = 7$$$, $$$k=0$$$ is a possible answer. Note that $$$k=4$$$ is also a possible answer because $$$(2 + 4) + (5 + 4) = (2 + 4) \oplus (5 + 4) = 15$$$.In the second test case, $$$(x+k)\oplus (y+k) = (6+k)\oplus (6+k) = 0$$$. However, $$$(x+k)+(y+k) > 0$$$ holds for every $$$k \ge 0$$$, implying that such an integer $$$k$$$ does not exist.