Mikasa

Description:

Input:

The first line contains a single integer $$$t$$$ ($$$1 \le t \le 30\,000$$$)  — the number of test cases.

The first and only line of each test case contains two integers $$$n$$$ and $$$m$$$ ($$$0 \le n, m \le 10^9$$$).

Output:

For each test case, print a single integer  — the answer to the problem.

Sample Input:

5
3 5
4 6
3 2
69 696
123456 654321

Sample Output:

4
3
0
640
530866

Note:

In the first test case, the sequence is $$$3 \oplus 0, 3 \oplus 1, 3 \oplus 2, 3 \oplus 3, 3 \oplus 4, 3 \oplus 5$$$, or $$$3, 2, 1, 0, 7, 6$$$. The smallest non-negative integer which isn't present in the sequence i. e. the $$$\operatorname{MEX}$$$ of the sequence is $$$4$$$.

In the second test case, the sequence is $$$4 \oplus 0, 4 \oplus 1, 4 \oplus 2, 4 \oplus 3, 4 \oplus 4, 4 \oplus 5, 4 \oplus 6$$$, or $$$4, 5, 6, 7, 0, 1, 2$$$. The smallest non-negative integer which isn't present in the sequence i. e. the $$$\operatorname{MEX}$$$ of the sequence is $$$3$$$.

In the third test case, the sequence is $$$3 \oplus 0, 3 \oplus 1, 3 \oplus 2$$$, or $$$3, 2, 1$$$. The smallest non-negative integer which isn't present in the sequence i. e. the $$$\operatorname{MEX}$$$ of the sequence is $$$0$$$.