#include <bits/stdc++.h>
using namespace std;
int main() {
  long double h, l, a;
  cin >> h >> l;
  cout << fixed << showpoint;
  cout << setprecision(13);
  a = abs((h * h) - (l * l));
  cout << (a / (2.0 * h));
  return 0;
}
