write a go solution for Description:
You are given two sequences a_1,a_2,...,a_n and b_1,b_2,...,b_n. Each element of both sequences is either 0, 1 or 2. The number of elements 0, 1, 2 in the sequence a is x_1, y_1, z_1 respectively, and the number of elements 0, 1, 2 in the sequence b is x_2, y_2, z_2 respectively.

You can rearrange the elements in both sequences a and b however you like. After that, let's define a sequence c as follows:

c_i=begincasesa_ib_i&mboxifa_i>b_i0&mboxifa_i=b_i-a_ib_i&mboxifa_i<b_iendcases

You'd like to make sum_i=1^nc_i (the sum of all elements of the sequence c) as large as possible. What is the maximum possible sum?

Input Format:
The first line contains one integer t (1<=t<=10^4) — the number of test cases.

Each test case consists of two lines. The first line of each test case contains three integers x_1, y_1, z_1 (0<=x_1,y_1,z_1<=10^8) — the number of 0-s, 1-s and 2-s in the sequence a.

The second line of each test case also contains three integers x_2, y_2, z_2 (0<=x_2,y_2,z_2<=10^8; x_1+y_1+z_1=x_2+y_2+z_2>0) — the number of 0-s, 1-s and 2-s in the sequence b.

Output Format:
For each test case, print the maximum possible sum of the sequence c.

Note:
In the first sample, one of the optimal solutions is:

a=2,0,1,1,0,2,1

b=1,0,1,0,2,1,0

c=2,0,0,0,0,2,0

In the second sample, one of the optimal solutions is:

a=0,2,0,0,0

b=1,1,0,1,0

c=0,2,0,0,0

In the third sample, the only possible solution is:

a=2

b=2

c=0. Output only the code with no comments, explanation, or additional text.