#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
#include <cmath>
#include <bitset>
#include <vector>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <algorithm>
#include <complex>
#include <unordered_map>
   
using namespace std;
typedef long long int ll;
typedef pair<int, int> P;

int main()
{
	double r, d;
	cin>>r>>d;
	printf("%.7lf\n", sqrt(d*d-r*r));
    return 0;
}