import java.util.Scanner;

public class Main {

	@SuppressWarnings("resource")
	public static void main(String args[]) {
		Scanner scanner = new Scanner(System.in);
		double r = scanner.nextDouble();
		double d = scanner.nextDouble();
		
		double X=d*d-r*r;
		
		for(double i=X;i>0;i--) {
			if(X==i*i) {
				System.out.println(i);
				return;
			}
		}
	}
}