**Problem Description**

Can you write a computer program that can compute such sums really quickly?

Given two integers n and m, you should compute the sum of all the integers from n to m. In other words,you should compute

**Input**

The first line contains the number of scenarios(<1000). Each scenario consists of a line containing the numbers n and m (−10^9 <= n <= m <=10^9).

**Output**

The output for every scenario begins with a line containing “Case #i: ”, where i is the number of the scenario starting at 1. Then print the sum of all integers from n to m.

**Sample Input**

3 1 100 -11 10 -89173 938749341

**Sample Output**

Case #1: 5050 Case #2: -11 Case #3: 440625159107385260

**Source**

武汉大学第二届“e鸣杯”程序设计竞赛2008