2019中国大学生程序设计竞赛（CCPC）

A - ^&^

Bit operation is a common computing method in computer science ,Now we have two positive integers AA and BB ,Please find a positive integer CC that minimize the value of the formula (A  xor  C)  &  (B  xor  C)(A  xor  C)  &  (B  xor  C) .Sometimes we can find a lot of CC to do this ,So you need to find the smallest CC that meets the criteria . 

For example ,Let's say AA is equal to 5 and BB is equal to 3 ,we can choose CC=1,3.... ,so the answer we're looking for CC is equal to 1. 

If the value of the expression is 0 when C=0, please print 1. 

Input

The input file contains TT test samples.(1<=TT<=100) 

The first line of input file is an integer TT. 

Then the TT lines contains 2 positive integers, AA and BB, (1≤A,B<2321≤A,B<232)OutputFor each test case,you should output the answer and a line for each answer. 
Sample Input

1
3 5

Sample Output

1


　　　由题意：找到最小C，使（A xor C）&(B xor C)最小。根据分配律，原式=(A&B) xor C；
　　A,B已知，则（A&B）为固定值，又根据xor（异或）知识：同为0，异为1，则要想使原式最小，C要==(A&B)才行，因为两个数异或运算，如果两个数相同，同为0，结果最小。
所以C=（A&B）。
　　又根据题意最后一句：If the value of the expression is 0 when C=0, please print 1. 
　　有代码：
　　　　

#include<iostream>
typedef long long ll;
using namespace std;
int main()
{
    ll t;
    cin>>t;
    while(t--)
    {
        ll a,b;
        cin>>a>>b;
        if((a&b)==0)
            printf("1
");
        else
            printf("%lld
",a&b);
    }
}