f(x) is series 1,2,-2,3,-3,3,4,-4,4,-4. Given two positions l and r, find the sum of all elements from l to r(l and r inclusive).

Input : First line of the input contains a single integer T denoting number of test cases. For each test case, two integers l and r are given.

Output: Print the answer in a single line.

Constraints

• 1 <= T <= 10, 1 <= l,r <= 10^12