import java.*;
public class erfen
{
	public static void main(String args[])
	{
		double a=1;
		double b=2;
		er(a,b);
	}
	public static void er(double a,double b)
	{
		 double x=0;
		 double sum=0;
		for(int i=0;i<8;i++)
		{
			x=(a+b)/2;
		 	sum=x*x-x-1;
			if(sum>0)
			{
				b=x;	
			
			}
			else
			{
				a=x;		
			}
			
		}
		System.out.println("the result is  "+x);
		
	}

}