import java.util.*;
import java.lang.*;
import java.io.*;

class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		Scanner  in = new Scanner(System.in);
		double a, y;
		a = in.nextDouble();
		if (a > 0) y=-a*a;
		else y=-a;
		System.out.print(y); 
	}
}