#include <stdio.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#include <functional>
#include <map>
#include <iomanip>
#include <math.h> 
#include <stack>
#include <queue>
#include <bitset>
#include <cstdlib>
#include <tuple>
#include <cctype>
#include <ctype.h>
#include <set>
#include <sstream>

using namespace std;



int main(){
	int i, j, k;
	double r, d;

	cin >> r >> d;

	cout << fixed << setprecision(10) << sqrt( d*d - r*r ) << endl;

	/*
	cout << sin(90) << endl;
	cout << cos(90) << endl;
	cout << tan(90) << endl;

	cout << d * sin(90) << endl;
	cout << d * cos(90) << endl;
	cout << d * tan(90) << endl;

	cout << r * sin(90) << endl;
	cout << r * cos(90) << endl;
	cout << r * tan(90) << endl;
	*/





	getchar();
	getchar();
	return 0;
}