import java.util.*;
import java.lang.*;
import java.io.*;
import java.math.*;

class Coordinates{
	public static void main (String[] args) throws java.lang.Exception {
		Scanner read = new Scanner(System.in);
		double x = read.nextDouble();
		double y = read.nextDouble();
		double u; 
		if((y >= x*x) && (y <= Math.exp(-x)) && (y <= Math.exp(x)))
			u = x+y;
		else 
			u = x-y;
		System.out.print(u);
	}
}