#include <bits/stdc++.h>
using namespace std;
const int inf = 1e9 + 7;
const int modc = 998244353;
void solve();
int main() {
  std::ios::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);
  solve();
  return 0;
}
void solve() {
  long double h, l;
  cin >> h >> l;
  cout << fixed << setprecision(12) << (l * l - h * h) / (2 * h) << endl;
}
