#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;

int main(){
	double a,b;
	cin >> a >> b;
	if(a == b){
		cout << fixed << setprecision(10) << sqrt(a * a + b * b) << endl;
		return 0;
	}
	if(a > b) swap(a,b);
	cout << fixed << setprecision(10) << sqrt((b + a) * (b - a)) << endl;
}