A.cpp

/*****                                            American International University Bangladesh (AIUB)                                                          
                                                              Hadiur Rahman Nabil
                                                                  Z3R0-DAY
                                                               
                                                          
*****/
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;


int main() 
{
 ll n,m;
 cin>>n;
 if(n%2==0)
 {
     cout<<n/2;
 }
 else{
     m=-(( n/2)+1);
     cout<< m;
 }
 


  


    return 0;
  }