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 x, eps, left, right, d, s;
    	int n=0;
    	x = in.nextDouble();
    	eps = in.nextDouble();
	    left=Math.atan(x);
	    right=x;
	    d=Math.abs(left-right);
	    s=x;
		while(d>eps)
		{
			n++;
			s*=(-1)*x*x;
			right+=s/(2*n+1);
			d=Math.abs(left-right);
		}
		System.out.print("left="+left+" right="+right+" n="+n+" d="+d); 
	}
}

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MC43IDAuMDAwMDAwMDAwMDE=

0.7 0.00000000001