CRS  Crying Series
Monir is a student of class 8. He loves to learn new logic from Mathematics. Divergent Geometric Series is an interesting topic to him. So, He starts practicing to find the sum of the series in his everyday life. So he pick a standard series for Nth term,
F(x) = (1)*1 + (1)^{2}* 2 + (1)^{3}* 3 + ..... + (1) ^{N}*N
In this case, He asks for your help to find the value (algebraic sum) of F(x) from given series. As you are a great programmer in our country.
Input
Every line of the input contains a single integer N denoting the number of terms in the series.
Constraints
 0 ≤ N ≤ 10^{15}
Output
For each test case, print a single line and the value (algebraic sum of all elements) of F(x) from given series.
Example
Input: 0 1 2 Output: 0 1 1
hide comments
asad:
20180702 14:36:30
thanks. @wisfaq 

wisfaq:
20180624 15:25:11
Be careful:


asad:
20180624 14:09:38
ok 

xynkt_99:
20180624 13:24:17
should be moved to tutorial 
Added by:  asad_IT 
Date:  20180624 
Time limit:  0.300s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All 
Resource:  Math 