Gauss

Carl Friedrich Gauß was a German mathematician.

When Gauß was in elementary school, his teacher J.G. Büttner asked the class to add up all the numbers from 1 to 100. Within a few seconds Gauß produced the correct answer, 5050.

Given two integers $n$ and $m$, write a program that computes the sum of every integer that is greater than or equal to $n$ and less than or equal to $m$. That is, compute the following value.

$\sum_{i=n}^{m} i = n + (n+1) + (n+2) + \dots + (m-1) + m$

The first line contains the number of test cases $T$.

Each test case consists of a single line containing two integers $n$ and $m$ separated by a space. ($-10^9 \le n \le m \le 10^9$)

For each test case, first print Scenario #i:, where $i$ is the test case number starting from 1. On the next line, print the sum of all integers from $n$ to $m$.

Print one blank line between the outputs of consecutive test cases.