Time Limit: 0.5 sec
Find the sum of N element of this series
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).
For each case, print the case number and Sum of first N element of the series.
Case 1: -1
Case 2: 1
Case 3: -2
Problem Setter: Murad Al Wajed [Bangladesh University of Business and Technology]