Please subscribe to the official Codeforces channel in Telegram via the link: https://t.me/codeforces_official.
×

Virtual contest is a way to take part in past contest, as close as possible to participation on time. It is supported only ACM-ICPC mode for virtual contests.
If you've seen these problems, a virtual contest is not for you - solve these problems in the archive.
If you just want to solve some problem from a contest, a virtual contest is not for you - solve this problem in the archive.
Never use someone else's code, read the tutorials or communicate with other person during a virtual contest.

No tag edit access

B. Margarite and the best present

time limit per test

1 secondmemory limit per test

256 megabytesinput

standard inputoutput

standard outputLittle girl Margarita is a big fan of competitive programming. She especially loves problems about arrays and queries on them.

Recently, she was presented with an array $$$a$$$ of the size of $$$10^9$$$ elements that is filled as follows:

- $$$a_1 = -1$$$
- $$$a_2 = 2$$$
- $$$a_3 = -3$$$
- $$$a_4 = 4$$$
- $$$a_5 = -5$$$
- And so on ...

That is, the value of the $$$i$$$-th element of the array $$$a$$$ is calculated using the formula $$$a_i = i \cdot (-1)^i$$$.

She immediately came up with $$$q$$$ queries on this array. Each query is described with two numbers: $$$l$$$ and $$$r$$$. The answer to a query is the sum of all the elements of the array at positions from $$$l$$$ to $$$r$$$ inclusive.

Margarita really wants to know the answer to each of the requests. She doesn't want to count all this manually, but unfortunately, she couldn't write the program that solves the problem either. She has turned to you — the best programmer.

Help her find the answers!

Input

The first line contains a single integer $$$q$$$ ($$$1 \le q \le 10^3$$$) — the number of the queries.

Each of the next $$$q$$$ lines contains two integers $$$l$$$ and $$$r$$$ ($$$1 \le l \le r \le 10^9$$$) — the descriptions of the queries.

Output

Print $$$q$$$ lines, each containing one number — the answer to the query.

Example

Input

5 1 3 2 5 5 5 4 4 2 3

Output

-2 -2 -5 4 -1

Note

In the first query, you need to find the sum of the elements of the array from position $$$1$$$ to position $$$3$$$. The sum is equal to $$$a_1 + a_2 + a_3 = -1 + 2 -3 = -2$$$.

In the second query, you need to find the sum of the elements of the array from position $$$2$$$ to position $$$5$$$. The sum is equal to $$$a_2 + a_3 + a_4 + a_5 = 2 -3 + 4 - 5 = -2$$$.

In the third query, you need to find the sum of the elements of the array from position $$$5$$$ to position $$$5$$$. The sum is equal to $$$a_5 = -5$$$.

In the fourth query, you need to find the sum of the elements of the array from position $$$4$$$ to position $$$4$$$. The sum is equal to $$$a_4 = 4$$$.

In the fifth query, you need to find the sum of the elements of the array from position $$$2$$$ to position $$$3$$$. The sum is equal to $$$a_2 + a_3 = 2 - 3 = -1$$$.

Codeforces (c) Copyright 2010-2018 Mike Mirzayanov

The only programming contests Web 2.0 platform

Server time: Dec/19/2018 07:30:29 (f2).

Desktop version, switch to mobile version.

Supported by

User lists

Name |
---|