#include <bits/stdc++.h>
using namespace std;
int main() {
  long double h, l;
  cin >> h >> l;
  long double y = l * l;
  long double z = h * h;
  long double x = y - z;
  long double temp = 2 * h;
  x = x / temp;
  cout << fixed << setprecision(13) << x << endl;
  return 0;
}
