CF1554C.Mikasa

You 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 $\operatorname{MEX}(1, 2021) = 0$.

给你两个整数 $n$ 和 $m$。求序列 $n \oplus 0, n \oplus 1, \ldots, n \oplus m$ 的 $\operatorname{MEX}$。其中，$\oplus$ 是按位异或运算符。

非负整数序列的 $\operatorname{MEX}$ 是未出现在该序列中的最小非负整数。例如，$\operatorname{MEX}(0, 1, 2, 4) = 3$，而 $\operatorname{MEX}(1, 2021) = 0$。

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 $m$ ($0 \le n, m \le 10^9$).

第一行包含一个整数 $t$（$1 \le t \le 30\,000$）—— 表示测试用例的数量。

每个测试用例仅有一行，包含两个整数 $n$ 和 $m$（$0 \le n, m \le 10^9$）。

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

对于每个测试用例，输出一个整数——即该问题的答案。

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 $0$.

在第一个测试用例中，序列为 $3 \oplus 0, 3 \oplus 1, 3 \oplus 2, 3 \oplus 3, 3 \oplus 4, 3 \oplus 5$，即 $3, 2, 1, 0, 7, 6$。该序列中未出现的最小非负整数（即该序列的 $\operatorname{MEX}$）为 $4$。

在第二个测试用例中，序列为 $4 \oplus 0, 4 \oplus 1, 4 \oplus 2, 4 \oplus 3, 4 \oplus 4, 4 \oplus 5, 4 \oplus 6$，即 $4, 5, 6, 7, 0, 1, 2$。该序列中未出现的最小非负整数（即该序列的 $\operatorname{MEX}$）为 $3$。

在第三个测试用例中，序列为 $3 \oplus 0, 3 \oplus 1, 3 \oplus 2$，即 $3, 2, 1$。该序列中未出现的最小非负整数（即该序列的 $\operatorname{MEX}$）为 $0$。