#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using vll = vector<ll>;
using vpp = vector<pair<ll, ll> >;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  double h, l;
  cin >> h >> l;
  l = h * h + l * l;
  l = l / 2;
  l = l / h;
  l -= h;
  cout.precision(10);
  cout << fixed << l;
  return 0;
}
