# 1673. GauB in Elementary School

Johann Carl Friedrich GauB (1777 – 1855) was one of the most important German mathematicians. For those of you who remember the Deutsche Mark, a picture of him was printed on the 10 – DM bill. In elementary school, his teacher J. G. Büttner tried to occupy the pupils by making them add up the integers from 1 to 100. The young GauB surprised everybody by producing the correct answers (5050) within seconds.

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

### 输入格式

The first line contains the number of scenarios. Each scenario consists of a line containing the numbers n and m (-10^9 ≤ n ≤ m ≤ 10^9).

### 输出格式

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

### 样例

Input
3
1 100
-11 10
-89173 938749341

Output
Scenario #1:
5050
Scenario #2:
-11
Scenario #3:
440625159107385260


57 人解决，109 人已尝试。

65 份提交通过，共有 389 份提交。

5.2 EMB 奖励。