package No400番台;

import java.util.Scanner;

public class Q419 {
	public static void main(String[] args) {
		new Q419().solver();
	}

	void solver() {
		Scanner sc = new Scanner(System.in);
		double a = sc.nextDouble();
		double b = sc.nextDouble();

		double ans = Math.sqrt(Math.abs(a * a - b * b));
		System.out.println(ans);
	}
}