After solving the Basic Gcd Problem, ZYB gives you a more difficult one:

Given an integer , find two subset  and  of  such that:

•  and 
• Let  and , there exists two permutations  and  such that for each , .

Please find two subsets with maximum value of .

输入描述:

There are multiple test cases. The first line of input contains an integer , indicating the number of test cases. 
For each test case, there is only one line containing an integer  () 
It's guaranteed that the sum of  of all test cases will not exceed .

输出描述:

For each test case, output an integer  in the first line. In the next  lines, each contains two integers  and  (), denoting the -th element in subset  and .
If there are multiple solutions, you can output any of them.

2
4
10

1
2 4
4
3 9
5 10
8 2
4 6