Easy Series

Time Limit: 0.5 sec

 

The Problem

Find the sum of N element of this series

-1+2-3+4-5+6…………N

 

The Input

First line contains one integer T denotes the number of test case. Then the following T (1<=T<=1000) lines contains an integer N(1<=N<=10^9).

 

The Output

For each case, print the case number and Sum of first N element of the series.

 

Sample Input

3

1

2

3

 

Sample Output

Case 1: -1

Case 2: 1

Case 3: -2

 

 

 

 

Problem Setter: Murad Al Wajed [Bangladesh University of Business and Technology]