## Problem Statement-

This problem Even Pair sum is taken from December long challenge 2020. let's read the problem statement.

You are given two positive integers $A$ and $B$. Find the number of pairs of positive integers $\left(X,Y\right)$ such that $1\le X\le A$$1\le Y\le B$ and $X+Y$ is even.

### Input

• The first line of the input contains a single integer $T$ denoting the number of test cases. The description of $T$ test cases follows.
• The first and only line of each test case contains two space-separated integers $A$ and $B$.

### Output

For each test case, print a single line containing one integer ― the number of valid pairs.

### Constraints

• $1\le T\le 1,000$
• $1\le A,B\le {10}^{9}$

Subtask #1 (10 points): $A,B\le 10$

Subtask #2 (10 points): $A,B\le 1,000$

Subtask #3 (80 points): original constraints

### Example Input

4
1 1
2 3
4 6
8 9


### Example Output

1
3
12
36

### Solution-

Hint- There is Very big role of even odd in this problem.
In this problem we have to calculate even and odd numbers till A and B.
because odd+odd=even
even +even =even
Here is my solution

Join Telegram Channel for solution.

1. use long long instead of int

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