import java.io.*;

class NewtonRaphson
{
// Calculates the square root of a number
// to a give accuracy using the
// Newton-Raphson method.
// (iterative version)

 public static void main(String[] args)
 throws IOException
 {
  double a,delta,sq;
  BufferedReader in = Text.open(System.in);
  System.out.print("Enter a number: ");
  a=Text.readDouble(in);
  System.out.print("Enter the accuracy factor: ");
  delta=Text.readDouble(in);
  sq=NRsqrt(a,delta);
  System.out.print("The calculated square root is: ");
  System.out.println(sq);
  sq=Math.sqrt(a);
  System.out.print("   System calculation gives  : ");
  System.out.println(sq);
 }

 public static double NRsqrt(double a,double delta)
 {
  double x=a,oldx;
  do
    {
     oldx=x;
     x=(x+a/x)/2;
    }
  while(Math.abs(x-oldx)>delta);
  return x;
 }

}