#include "bits/stdc++.h"

using namespace std;

using ll = long long;
using ld = long double;

const double PI = 3.1415926535897932384626433832795;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { -1, 0, 1, 0 };

int gcd(int x, int y) { return y ? gcd(y, x % y) : x; }
ll gcd(ll x, ll y) { return y ? gcd(y, x % y) : x; }
int lcm(int x, int y) { return x / gcd(x, y) * y; }
ll lcm(ll x, ll y) { return x / gcd(x, y) * y; }

int main() {
	//ios::sync_with_stdio(false);
	//cin.tie(0);

	double r, d;
	cin >> r >> d;

	// al^2 + lo^2 = ao^2
	// al^2 + r^2 = d^2
	// al^2 = d^2 ^ - r^2

	double ans = sqrt(d * d - r * r);
	printf("%.12lf\n", ans);
	return 0;
}