import java.util.*;
public class Main
{
public static void main
(String[] args
) { Scanner sc
= new Scanner
(System.
in); int n = sc.nextInt();
int ne,no;
long sum = 0;
if(n%2==0) {
ne = n/2;
no = n/2;
sum = (long)ne;
}else{
ne = n/2;
no = (n/2)+1;
sum = -1*((long)ne+1);
}
}
}
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