#include <bits/stdc++.h>
using namespace std;
int main() {
  int t = 1;
  while (t--) {
    long double H, L;
    cin >> H >> L;
    long double h = ((L * L) - (H * H)) / (2 * H);
    cout << fixed << setprecision(12) << h;
  }
}
