#include <bits/stdc++.h>
using namespace std;
class DebugStream {
} LOG;
template <typename T>
DebugStream &operator<<(DebugStream &s, const T &) {
  return s;
}
mt19937 rnd(time(NULL));
const int maxN = 1e5 + 9, maxV = 1e6 + 9, MOD = 1e9 + 7, SQ = 335, lg = 20,
          bs = 29;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  long double H, L;
  cin >> H >> L;
  long double uno = atan(L / H);
  long double dos = 3.141592653589793238462643383279502884L / 2 - uno;
  long double tres = dos - uno;
  long double resp = abs(tan(tres) * L);
  cout << fixed << setprecision(12) << resp << '\n';
}
