B. Margarite and the best present

Little 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 aa of the size of 109109 elements that is filled as follows:

  • a1=−1a1=−1
  • a2=2a2=2
  • a3=−3a3=−3
  • a4=4a4=4
  • a5=−5a5=−5
  • And so on ...

That is, the value of the ii-th element of the array aa is calculated using the formula ai=i⋅(−1)iai=i⋅(−1)i.

She immediately came up with qq queries on this array. Each query is described with two numbers: ll and rr. The answer to a query is the sum of all the elements of the array at positions from ll to rr 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 qq (1≤q≤1031≤q≤103) — the number of the queries.

Each of the next qq lines contains two integers ll and rr (1≤l≤r≤1091≤l≤r≤109) — the descriptions of the queries.

Output

Print qq 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

代码：

#include<iostream>
#include<algorithm>
#include<cstring>
#include<string>
#include<cstdio>
#include<cmath>
#include<set>
#include<map>
using namespace std;
#define ll long long
#define inf 0x3f3f3f3f
#define mem(a,b) memset(a,b,sizeof(a))
#define closeio std::ios::sync_with_stdio(false)
 
int main()
{
	ll n,a,b,i,t;
	cin>>n;
	while(n--)
	{
		cin>>a>>b;
		if(a%2==1)
		{
			if(b%2==1)
				t=(b-a)/2-b;
			else
				t=(b+1-a)/2;		
		}
		else
		{
			if(b%2==1)
				t=(a-b-1)/2;
			else
				t=(a-b)/2+b;
		}
		cout<<t<<endl;
	}	
	return 0;
}