using System;

public class Program

{

    public static void Main()

    {

        int totalOdds = 0;

        int totalEvens = 0;

        for(int i = 1; i < 176; i++)

        {

            if(i % 2 == 0)

                totalEvens+=i;

            if(i % 2 != 0)

                totalOdds+=i;

        }

        Console.WriteLine(Math.Abs(totalEvens - totalOdds));

    }

}