#include<iostream>
#include <math.h>
#include <string>
#include <iomanip>
using namespace std;

int main(){
	double a, b;
	double answer;
	cin >> a >> b ;
	if (a > b){
		answer = sqrt(a*a - b*b);
		printf("%.10f\n", answer);
	}
	else if (a < b){
		answer = sqrt(b*b - a*a);
		printf("%.10f\n", answer);
	}else{
		answer = a*sqrt(2);
		printf("%.10f\n", answer);
	}
	



	return 0;
}