#pragma GCC optimize("Ofast")
#include<iostream>
#include<stdio.h>
#include<algorithm>
#include<vector>
#include<string.h>
#include<math.h>
#include<map>
#include<iomanip>
#include<queue>

const long long INF = 1e17+7;
const long long MOD = 1e9+7;
const double PI=acos(-1);

using namespace std;

int main(){
	double r,d;
	cin >> r >> d;
	double x=sqrt(d*d-r*r);
	cout << fixed << setprecision(15) << x << endl;
	return 0;
}