#include <bits/stdc++.h>
#define PI 3.14159265359
using namespace std;
const int64_t MOD = 1e9 + 7;

int main() {
	double r, d;
	cin >> r >> d;

	double AL = sqrt(d * d - r * r);

	cout << fixed << setprecision(10) << AL << endl;
}