#include<iostream>
#include<math.h>
#include<iomanip>

using namespace std;

int main() {

	double r = 0, d = 0, ans=0;

	cin >> r >> d;
	ans = sqrt(pow(d, 2) - pow(r, 2));
	cout << showpoint;
	cout << setprecision(12) << ans;

	return 0;
}