For given integers $n$ and $m$, let's call a pair of arrays $a$ and $b$ of integers good, if they satisfy the following conditions:
$a$and$b$have the same length, let their length be$k$.$k \ge 2$and$a_1 = 0, a_k = n, b_1 = 0, b_k = m$.- For each
$1 \lt i \le k$the following holds:$a_i \geq a_{i - 1}$,$b_i \geq b_{i - 1}$, and$a_i + b_i \neq a_{i - 1} + b_{i - 1}$.
Find the sum of $|a|$ over all good pairs of arrays $(a,b)$. Since the answer can be very large, output it modulo $10^9 + 7$.
Input
The input consists of multiple test cases. The first line contains a single integer $t (1 \leq t \leq 10^4)$ — the number of test cases. The description of the test cases follows.
The only line of each test case contains two integers $n$ and $m$ $(1 \leq n, m \leq 5 \cdot 10^6)$.
It is guaranteed that the sum of $n$ over all test cases does not exceed $5 \cdot 10^6$ and the sum of $m$ over all test cases does not exceed $5 \cdot 10^6$.
Output
For each test case, output a single integer — the sum of $|a|$ over all good pairs of arrays $(a,b)$ modulo $10^9 + 7$.
Note
In the first testcase, the good pairs of arrays are
$([0, 1], [0, 1])$, length =$2$.$([0, 1, 1], [0, 0, 1])$, length =$3$.$([0, 0, 1], [0, 1, 1])$, length =$3$.
Hence the sum of the lengths would be ${2 + 3 + 3} = 8$.
样例
4
1 1
1 2
2 2
100 100
8
26
101
886336572
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