#include <bits/stdc++.h>
using namespace std;
using lld = long long int;
using dbl = numeric_limits<double>;
int main() {
  lld h, l;
  cin >> h >> l;
  double ans = (l * l - h * h);
  ans = ans / (2 * h);
  cout.precision(dbl::max_digits10);
  cout << ans << endl;
  return 0;
}
