using System;

public class Program

{

    public static void Main()

    {

        for(int i=1000;i>-1000;i--){

            int v = Program.GetResult(i);

            if(v<1000){

                Console.WriteLine(i);

                return;

            }

        }

    }

    public static int GetResult(int x){

        return (15*x*x)-(3*x)-12;

    }

}