C. Mikasatime limit per test1 secondmemory limit per test256 megabytesinputstandard inputoutputstandard outputYou are given two integers n and m. Find the \operatorname{MEX} of the sequence n \oplus 0, n \oplus 1, \ldots, n \oplus m. Here, \oplus is the bitwise XOR operator.\operatorname{MEX} of the sequence of non-negative integers is the smallest non-negative integer that doesn't appear in this sequence. For example, \operatorname{MEX}(0, 1, 2, 4) = 3, and \operatorname{MEX}(1, 2021) = 0. InputThe 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).OutputFor each test case, print a single integer  — the answer to the problem.ExampleInput
5
3 5
4 6
3 2
69 696
123456 654321
Output
4
3
0
640
530866
NoteIn 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.
5
3 5
4 6
3 2
69 696
123456 654321

4 3 0 640 530866 
['binary search', 'bitmasks', 'greedy', 'implementation', '*1800']