#include <bits/stdc++.h>
#define rep(i,n)for(long long i=0;i<(n);i++)
using namespace std;
typedef unsigned long long ull;
typedef long long ll;
const ll INF=1e18;
const int MOD=1e9+7;
const double pi=acos(-1);

int main(){
  double d,r;
  cin >> r >> d;
  cout << fixed << setprecision(10) << sqrt(d*d-r*r) << endl;
  
}