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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
Σ m i = n + (n + 1) + (n + 2) + ... + (m - 1) + m i = n
The first line contains the number of scenarios. Each scenario consists of a line containing the numbers n and m (-109 ≤ n ≤ m ≤ 109).
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.
3 1 100 -11 10 -89173 938749341
Scenario #1: 5050 Scenario #2: -11 Scenario #3: 440625159107385260